Whether there's a blizzard or a heat wave (remember those?), three Twin Cities bars in one neighborhood are impervious to extreme weather. That's because the latest trend in North Loop cocktail lounges is to go underground — literally — with subterranean escapes that create an atmosphere all their own.

Billy After Dark, a speakeasy-style cocktail bar beneath Billy Sushi, celebrates the building's 1887 foundation by spotlighting exposed stone walls. In front of those walls: trees that ring the entire space. And that's not all. The ceiling is inlaid with pinholes that light up with LED stars. It's not just removed from the elements upstairs; it's practically another planet.

"It feels like you are not in the basement," says owner Billy Tserenbat. "You feel like you are in the street. And after a few cocktails, you will be like, this is really unique. It's creating a whole different experience."

These bars take their cues, in a way, from black box theaters. They're blank slates, ready to be transformed according to the proprietor's vision — even if that vision is radically different from whatever's going on above ground.

Take Maison Margaux, David Fhima's multilevel French restaurant. Upstairs, the lights are bright and the prevailing color scheme is white on white. Downstairs, there's a dimly lit cavern that's been decked out in red velvet, a tribute to the belle époque era of decadence in pre-World War I Paris.

"It's a more sophisticated debauchery," says co-owner Eli Fhima. "We thought it'd be fun to have such a stark difference from the dining room, with a sultry, swanky bar meant to express the theatrics and the elements of the night."

Here, too, the building's history is woven into the scenery. The 1884 bricks are exposed in the basement. "We're boasting the history, while also playing into the catacomb-esque, underneath-Paris kind of vibe."

And there's another reason the basement is a desirable location to install a bar. The cooler temperature and lack of sunlight is the "close-to-perfect condition for storing wine," Fhima says.

The lack of windows is an advantage nearby at the Flora Room, too. Lounging with a cocktail beneath Daniel del Prado's new restaurant Porzana, "it can be any time of day or year," says bar director Megan Luedtke. "You can kind of forget about whatever is happening outside. It feels like you don't even know what city you're in. I think that's the allure."

The space is dim, yet filled with plants, while the menu is decidedly tropical, further contributing to the sense of escapism.

Says Luedtke, "Anywhere you can cozy up with good people and good energy and just forget about the snow is my favorite."

Three to try

Don't Sweat the Technique
Billy After Dark, 120 1st Av. NE., Mpls., billyafterdark.com
Drinks and bites are inspired by those found in Japanese cocktail bars, including this lemon- and peach-laced Irish whiskey cocktail that gets set ablaze in a shower of cinnamon.

Note: the website is designed to look like spam; it is a speakeasy, after all.

World's Fair 1889
Maison Margaux Underground Bar, 224 N. 1st St., Mpls., maisonmargauxmpls.com
Emphasizing the pre-World War I Paris vibes, this spin on the espresso martini — with rum, sweet vermouth and espresso-infused Campari — is named after the city's great exposition.

Miami Girl
Flora Room, 200 N. 1st St., Mpls., floraroommpls.com
Truly tropical, this cocktail of coconut gin, star fruit, orgeat and lime is served in a pink ceramic penguin — a nod to owner Daniel del Prado's native Argentina.