Here is edited info I found on the Internet: The Tianguis Cultural del Chopo is a Saturday flea market known locally as El Chopo. Since the end of the eighties, the Tianguis del Chopo has been at a location very near subway station Metro Buenavista.
Originally, the Tianguis was a place for hippies to trade sixties memorabilia including not only records but also clothing, magazines, books and other collectibles. Eventually, the Tianguis has also given place to more recent musical styles like metal, goth, punk, grunge and ska, among others. Almost always, some local and touring bands play live gigs at the back of the market, where can also be found the casual traders standing and looking up for that rare and collectable record or CDs.
I live very close to this place and it is interesting to go there.