It's basically this English dude traveling all around the world and meeting gangs...
"Ross Kemp on Gangs is a BAFTA award-winning documentary series shown on Sky1 then repeated on Sky3. On 20 May 2007 the series won a BAFTA award for best factual series. The show is hosted by actor Ross Kemp, best known for his role of Grant Mitchell in the show EastEnders. Kemp's character on Eastenders has been involved in several storylines involving gangs.
On the show Kemp travels around the world talking to gang members, locals who have been affected by gang violence, and the authorities who are attempting to combat the problem. In each episode he attempts to establish contacts within the gangs who can arrange interviews with the gangs' leaders."
http://en.wikipedia.org/wiki/Ross_Kemp_on_Gangs
It's a lot better than Gangland imo.
I just picked up a two DVD pack which include St. Louis, Poland, El Salvador, Cape Town, Moscow, Jamaica, Colombia, and East Timor. Pretty interesting, cause it is not always the same shit...