Sure, a rooftop infinity pool looks amazing. Who wouldn’t want to take a dip while taking in the New York City skyline? But summer is fleeting, so designers are bringing the glamour inside, transforming what was once a dreary afterthought of the fitness center—the lowly lap pool—into a showstopping destination.

“The ultimate luxury for New York City is a swimming pool,” says Ryan Korban, who designed the interiors for the NoHo condo 40 Bleecker, including the 58-foot long saltwater pool.

Swimming indoors sounds lovely until you actually have to take a windowless, subterranean space and turn it into something amazing, not austere. Materials must exude luxury, but be hardy enough to withstand a damp atmosphere and harsh chemicals like chlorine. And in a condo where serious swimmers may share the water with splashing toddlers, the space needs to have a broad appeal, all while staying in character with a luxury building.

For a statement tower, like Rose Hill, a condo in NoMad that will open next year, your pool has to stand out too. The 45-story building, developed by the Rockefeller Group, the 91-year-old real-estate company that built Rockefeller Center, is a nod to Art Deco New York, with a bronze-tone façade and a lobby with a black marble fireplace, walnut paneling, and handcrafted metalwork. The 50-foot pool is just as sultry, with deep turquoise tiles, handmade in Vermont, and a mosaic of a woman swimming, surrounded by sunrays, a nod to Rockefeller Center.

A pool “is not just a simple space,” says Ximena Rodriguez, the director of interior design for CetraRuddy, which designed the building and interiors. “You have to carry the essence of the interior design into the pool; it has to feel like it belongs.”