“There’s nothing more Finnish than a sauna,” says Jasper Pääkkönen, co-founder of Löyly, which opened in 2016 and is the leading place to perspire in a city spoiled for choice. The striking waterfront facility uses wind and solar power, as well as sustainably sourced timber; its draw is similarly au naturel. “There’s no hierarchies” in a sauna “because you’re at your barest—literally,” Pääkkönen says. A two-hour session costs $22. —Eli Meixler
Correction: August 24
The original version of this story misstated Löyly’s power sources. It uses wind and solar power, not wind and hydropower.