Sixteen designers arrive in New York City, but a twist finds their launch party turning into an unconventional-materials challenge. Here, they must use party decorations to create their first look.

The designers must create an outfit to flatter all body types, and the challenge proves to be more difficult for some than others. Guest judge Nina Dobrev.

In Project Runway's first blacklight challenge, the designers have to create a look that sparkles not only in daylight, but under blacklights under the runway as well. Anxieties rise when the unusual materials leave many of the designers in the dark. Jaime King joins the judges this week.

The group creates swimsuits in a Heidi Klum Swimwear challenge; a lack of swimsuit experience sorely tests some contestants.

Business savvy is tested in this team challenge; designers must pitch collection ideas to raise money from a group of mystery investors.

A press-event bash turns into a challenge, spoiling the designers' festive mood. Model Emily Ratajkowski is the guest judge.

The designers recharge at Universal Studios Orlando, and must take in inspiration to design a look for Urban Jungle.

The second Team Challenge of the season leads to tensions and tantrums as the designers are forced to work together to create three-piece collections for a SoHo pop-up shop; Kelly Osbourne returns as a guest judge.

The designers' loved ones arrive from home for emotional reunions, but drama quickly takes over when the clothiers discover their special visitors will also be their clients, and ,000 is on the line. Guest judges: Olivia Culpo and Katia Beauchamp.

The designers go on a helicopter ride above New York; the designers must create an editorial, high fashion look for ''Marie Claire'' magazine.

The first-ever hybrid challenge tasks the clothiers to fashion innovative avant-garde looks by using conventional fabric and unconventional metal-themed materials.

The designers take a trip to an unlikely destination in the twisting, turning final challenge, which determines which designers will compete at New York Fashion Week.

In Part 1 of the two-part Season 15 finale, Timballoonn visits the designers at home, but not all of their creations impress him. The clothiers return to New York and try to wow the judges with three pieces from their collection. Guest judge: Michael Kors.

New York Fashion Week arrives in the Season 15 finale. Here, the designers scramble to put the final touches on their collections, and the winner is then revealed. Guest judge: Zendaya.

The designers reconvene to reflect on the highs, lows and memories from the season.