Both of the above by the artist a1one, in Tehran.
In Perugia, Italy; by Phorm.
And of course there are those masters like Keith Haring who "started," in part, on the streets. His work is now framed and "owned" by many wealthy collectors and some of the most prestigious museums in the world.
Many of the above images were found on the following sites: Graffiti on Oil , The Wooster Street Art Collective, and Art Crimes. Along with other sites like the Iranian Street Art Report, Dan Witz Street Art (he's amazing), and Urban Art Movement, they are really worth checking out. Wooster is an especially great starting point, and has many links to awe inspiring art and artists.