This Belle Époque–style building's vast wooden dance floor is the place to be late on Thursday night, when it hosts Niño Bien (11/15–4147–8687), one of the most popular milongas in town (reservations are essential). The mix of older couples and younger dancers means you see very different styles in one place; all respect the traditional cabeceo (nonverbal invitation to dance) and partnership rules. Other milongas are held on Friday and Saturday nights.
Note that Centro Región Leonesa is in the Constitución district but just four or five blocks outside San Telmo.
Humberto I 1462, Buenos Aires, Buenos Aires, C1103AAD, Argentina