Keystone Towers Condo 2020 NE 135 St Miami Built in 1969, Keystone Towers is a 200 unit condominium located in the San Souci/Keystone Islands submarket in Miami, Florida. About Keystone Towers. Discover your new place at Keystone Towers. This property is situated at 2000-2020 NE 135th St. in the 33181 area [...]