Diseases that were largely eradicated in the United States a generation ago - whooping cough, measles, mumps - are returning, in part because nervous parents are skipping their children's shots. "Vaccines - Calling the Shots" takes viewers around the world to track epidemics, explore the science behind vaccinations and shed light on the risks of opting out. The program features scientists, pediatricians, psychologists, anthropologists and parents wrestling with vaccine-related questions.

Our lives are going digital. We shop, bank, and even date online. Computers hold our treasured photographs, private emails, and all of our personal information. This data is precious-and cybercriminals want it. Now, NOVA goes behind the scenes of the fast-paced world of cryptography to meet the scientists battling to keep our data safe. They are experts in extreme physics, math, and a new field called "ultra-paranoid computing", all working to forge unbreakable codes and build ultra-fast computers. From the sleuths who decoded the world's most advanced cyber weapon to scientists who believe they can store a password in your unconscious brain, NOVA investigates how a new global geek squad is harnessing cutting-edge science-all to stay one step ahead of the hackers.

The disappearance of Flight MH370 stunned the world. In an era of smart-phones and GPS, how could a 270-ton passenger jet vanish into thin air? It was a rude awakening for all of us, showing just how far we are from the world we imagined we lived in-in which every move is monitored all the time. NOVA tells the inside story of the search for Flight MH370 and meets the key players from all corners of the globe who have spent months searching for the lost plane. In the search for answers, we'll reveal how today's planes must fly through vast radar "blind spots", and investigate new technologies that could allow ground stations and satellites to track planes automatically, without pilot intervention, even in remote areas with no radar coverage. What will it take to guarantee that in the future, nothing will ever be 'lost' again?

In December, 2013, in a small village in West Africa, a young boy died from the dreaded disease, Ebola. Over the next nine months the virulent hugger would claim more victims than all previous Ebola epidemics put together. And for the first time, the disease escaped the isolated, rural villages where it had first appeared and traveled in infected patients by air to densely populated cities in several African countries. As the epidemic threatens to spiral out of control, NOVA reports from the hot zone, where courageous medical teams struggle to cope with a flood of victims, and in labs where scientists are racing to test vaccines and find a cure. "Surviving Ebola" includes chilling first-hand interviews of what it's like to catch-and-survive this terrible affliction.

The first stage in human flight didn't begin with the Wright brothers at Kitty Hawk, but with daring inventors and aeronauts in 18th century Paris. In a period of just 19 months, humanity not only left the ground for the first time-a moment as significant as the Apollo moon landing-but thanks to a handful of brilliant and colorful pioneers, developed all the essential features of today's hot air and gas balloons. Their exploits fascinated Benjamin Franklin, who was serving in Paris as the American ambassador. He reported that these early flights brought tens of thousands of citizens into the streets to watch the spectacle. To explore this burst of innovation, NOVA recreates key flights, including the world's first manned voyage that took place on November 21, 1783. Joining the team will be a descendant of the Montgolfier brothers, inventors of the hot-air balloon, who will build an accurate replica of the fragile paper and canvas craft using 18th century tools and materials. NOVA reveals the secrets of how the Montgolfiers invented flight and relives the experiences of the balloon pioneers who left Earth for the first time.

When World War I began in 1914, the air forces of the opposing nations consisted of handfuls of rickety biplanes from which pilots occasionally took pot shots at one another with rifles. By the war's end, the essential blueprint of the modern fighter had emerged: it was now an efficient hugging machine that limited the average life expectancy of a front line pilot to just a few weeks. To trace the story of this astonishingly rapid technological revolution, NOVA takes viewers inside The Vintage Aviator, a New Zealand-based outfit of aviation buffs dedicated to bringing back classic World War I fighters such as the SE5A and Albatros DV. NOVA joins the team as they discover the secrets of some of aviation's most colorful and deadly early flying machines and explores how their impact played a key role in the nightmare slaughter on the Western Front.

Almost a century ago, paleontologists found the first tantalizing hints of a monster even bigger than Tyrannosaurus rex, perhaps the largest predator ever to roam the Earth: spectacular fossil bones from a dinosaur dubbed Spinosaurus. But the fossils were completely destroyed during a World War II Allied bombing raid, leaving only drawings, questions, and a mystery: What was Spinosaurus? Now, the discovery of new bones in a Moroccan cliff face is reopening the investigation into this epic beast. What did it feed on and how? Why did it grow so big? We follow the paleontologists who are reconstructing this terrifying carnivore, revealing a 53-foot-long behemoth with a huge dorsal sail, enormous, scimitar-like claws, and massive jaws tapered toward the front like a crocodile. Bringing together experts in paleontology, geology, climatology and paleobotany, this NOVA/National Geographic special brings to life the lost world over which Spinosaurus reigned more than 65 million years ago.

In central China, a vast underground mausoleum conceals a life-size terracotta army of cavalry, infantry, horses, chariots, weapons, administrators, acrobats, and musicians, all built to serve China's first emperor, Qin Shi Huang Di, in the afterlife. Lost and forgotten for over 2,200 years, this clay army, 8,000-strong, stands poised to help the First Emperor rule again beyond the grave. Now, a new archaeological campaign is probing the thousands of figures entombed in the mausoleum. With exclusive access to pioneering research, "Emperor's Ghost Army" reveals how the Emperor directed the manufacture of the tens of thousands of bronze weapons carried by the clay soldiers. NOVA tests the power of these weapons with high-action experiments and reports on revolutionary 3D computer modeling techniques that are revealing new insights into how the clay figures were made, revealing in the process the secrets of one of archaeology's greatest discoveries.

Just before 11 a.m. on March 22, 2014, an ominous rumble startled the residents of the little town of Oso, Washington, about an hour's drive from Seattle. It was the terrifying sound of the United States' deadliest landslide in decades. In less than two minutes, a 250 acre field of debris 20 feet deep slammed into a neighborhood of 35 homes. In the wake of the tragedy, geomorphologists are tracing the geological history of Oso to explain why the site was so unstable. But Oso isn't alone. Globally, landslides and other ground failures cost more lives and money each year than all other natural disasters combined. The threat of bigger, more frequent landslides is growing as climate change increases intense precipitation events. As NOVA follows scientists surveying landslide danger zones, discover how and why landslides happen and how new laser monitoring technologies may help predict landslides before disaster strikes.

Everyone knows Neil Armstrong was the first to set foot on the moon. But this modest and unassuming man was determined to stay out of the spotlight. NOVA presents an intimate portrait of Armstrong through interviews with his family and friends, many of whom have never spoken publicly before. Discover and relive his achievements before and after Apollo, from his time as a Navy combat veteran and later as a pioneer of high-speed flight to his leading role in the inquiry into the Challenger disaster and his efforts to encourage young people to take to the skies.

Scientists upgrade the Large Hadron Collider to higher power in 2015 so that they can look at the world's tiniest particles.

Efforts to secure, raise and salvage the Costa Concordia cruise ship which capsized off the Italian coast on Jan. 13, 2012, hugging 32 people.

In a leafy suburb near Tampa, Florida, on February 28, 2013, a giant hole opened up under the bedroom floor of Jeffrey Bush, swallowing him as he slept. His body was never found. Bush was a victim of a sinkhole-a worldwide hazard that lurks wherever limestone and other water-soluble rocks underpin the soil. When carbon dioxide from the air dissolves in rainwater, it forms a weak acid that attacks soft rocks, riddling them with holes like Swiss cheese. Sinkholes can occur gradually when the surface subsides into bowl shaped depressions or suddenly when the ground gives way. These geological hazards have swallowed highways, apartment buildings, horses, camels, even golfers, with monster-size holes cracking the earth from Siberia to Louisiana. Filled with compelling eyewitness video of dramatic collapses, and following scientists as they explore the underlying forces behind these natural disasters, NOVA travels the globe to investigate what it's like to have your world vanish beneath your feet.

One of the ancient world's most iconic buildings, the Colosseum is a monument to Roman imperial power and cruelty. Its graceful lines and harmonious proportions concealed a highly efficient design and advanced construction methods that made hundreds of arches out of 100,000 tons of stone. In its elliptical arena, tens of thousands of gladiators, slaves, prisoners, and wild animals met their passings. Ancient texts report lions and elephants emerging from beneath the floor, as if by magic, to ravage gladiators and people condemned to passing. Then, just as quickly, the Colosseum could be flooded with so much water that ships could engage in sea battles to the delight of the crowd. Now, archaeologists and engineers are teaming up to recreate a 25-foot lifting machine and trap door system capable of releasing a wolf into the Colosseum's arena for the first time in 1,500 years. Do they have what it takes to replicate the innovation and ingenuity of the Romans?

More than 2,000 years ago, the thriving city of Petra rose up in the bone-dry desert of what is now Jordan. An oasis of culture and abundance, the city was built by wealthy merchants whose camel caravans transported incense and spices from the Arabian Gulf. They carved spectacular temple-tombs into its soaring cliffs, raised a monumental Great Temple at its heart, and devised an ingenious system that channeled water to vineyards, bathhouses, fountains, and pools. But following a catastrophic earthquake and a slump in its desert trade routes, Petra's unique culture faded and was lost to most of the world for nearly a thousand years. Now, in a daring experiment, an archaeologist and sculptors team up to carve an iconic temple-tomb to find out how the ancient people of Petra built their city of stone. Meanwhile, scientists using remote sensors and hydraulic flumes uncover the vast city and its sophisticated water system. The race is on to discover how these nomads created this oasis of culture in one of the harshest climates on Earth.

Whether serving as Christian church, Islamic mosque, or secular museum, Hagia Sophia and its saring dome have inspired reverence and awe. For 800 years, it was the largest enclosed building in the world-the Statue of Liberty can fit beneath its dome with room to spare. How has it survived its location on one of the world's most active seismic faults, which has inflicted a dozen devastating earthquakes since it was built in 537? As Istanbul braces for the next big quake, a team of architects and engineers is urgently investigating Hagia Sophia's seismic secrets. Follow engineers as they build a massive 8-ton model of the building's core structure, place it on a motorized shake table, and hit it with a series of simulated quakes, pushing it collapse-a fate that the team is determined to avoid with the real building.

Join NOVA on a mathematical mystery tour-a provocative exploration of math's astonishing power across the centuries. We discover math's signature in the swirl of a nautilus shell, the whirlpool of a galaxy, and the spiral in the center of a sunflower. Math was essential to everything from the first wireless radio transmissions to the prediction and discovery of the Higgs boson and the successful landing of rovers on Mars. Astrophysicist and writer Mario Livio, along with a colorful cast of mathematicians, physicists, and engineers, follow math from Pythagoras to Einstein and beyond. It all leads to the ultimate riddle: Is math a human invention or the discovery of the language of the universe?.

Twenty-five years ago, NASA launched one of the most ambitious experiments in the history of astronomy: the Hubble Space Telescope. In honor of Hubble's landmark anniversary, NOVA tells the remarkable story of the telescope that forever changed our understanding of the cosmos. But Hubble's early days nearly doomed it to failure: a one-millimeter engineering blunder had turned the billion-dollar telescope into an object of ridicule. It fell to five heroic astronauts in a daring mission to return Hubble to the cutting edge of science. This single telescope has helped astronomers pinpoint the age of the universe, revealed the birthplace of stars and planets, advanced our understanding of dark energy and cosmic expansion, and uncovered black holes lurking at the heart of galaxies. Join NOVA for the story of this magnificent machine and its astonishing discoveries.

Long before 9/11, a far deadlier, little-known attack from the ocean depths struck our shores, lasting three-and-a-half years and claiming 5,000 lives. Now, famed undersea explorer Bob Ballard, discoverer of the Titanic, investigates the wreck of one of the attack craft, a German submarine that lies at the bottom of the gulf just a few miles off New Orleans. U-166 was part of Operation Drumbeat, a highly successful U-boat operation that caught East Coast cities and shipping almost completely unprepared. Ballard probes the wreck and unravels a dramatic mystery in the official story of the sub's sinking.

Sharply rising carbon emissions are entering Earth's seas at a staggering rate, raising their acidity. Learn how scientists are researching the effects and looking for solutions.

spacecraft New Horizon's historic flyby of Pluto, the culmination of a nine-year, three-billion-mile journey, reveals the first-ever detailed images of Pluto.

NOVA reveals the minute-by-minute story of the Fukushima nuclear crisis-the one you know about, and the one you likely don't: the perilously close call at the other Fukushima nuclear power plant a few miles away from the meltdowns. With unprecedented access inside both Fukushima nuclear power plants, NOVA speaks with workers who were there during the harrowing days-a crisis that began as a natural a disaster but was made worse by human beings. But why did the worst happen at one plant while another that faced nearly identical challenges emerged unscathed? It may come down to the skill and knowledge of one man, who has worked there since they started construction. These are crucial questions as the company that runs both plants, TEPCO, tries to clean up an unprecedented radioactive mess and seeks to reopen the plant that was just barely saved.