http://www.welcomeargentina.com/tand...able-rock.html
Interesting tidbit from
Wikipedia:
The Moving Stone toppled on February 29, 1912, and split into two pieces at the bottom of the hill. [...] As of May 2007, a replica was set up in the same place where the original stood. Although the replica was made by engineering students, it is cemented in place and does not teeter the way the original did.