In its beginnings, the quarter was inhabited by the wealthiest families of Buenos Aires until 1871's Yellow Fever epidemic forced them to move North. With the passing of time, San Telma's appearance changed and it became a sightseeing must' in which old time's valuable architecture can be appreciated.
Among the interest spots you'll find the Orthodox Russian Church (1904), La Defensa" Alley (typical eighteenth century large house that recreates the Colonial Buenos Aires) and Colonel Manuel Dorrego Square (every Sunday from 10 a. m. to 5 p. m. there's an antiques fair), where you can spend some time at a coffee shop, tango or jazz dance clubs.
The virtue of San Telmo neighborhood lies on those interesting places one gets to know while walking, while going through stone pavement and narrow streets that surround colonial buildings, many of which act as antique dealers and ateliers. If you want to feel something different, it's worth the visit.