As Kaziganthe said 'q3 engine' I thought I mention that in the Quake3 mod Urban Terror there are several of these styles done in a fashion.
Pext wrote:- islam stuff ( al hambra, etc... )
In base Urban Terror there's (more arabic than islam) Riyadh, Algiers and Sands (last one complete with Saddam Hussein posters) and several 3rd party maps with arabic influences like Sliema and Druglord 2: Harambique.
seremtan wrote:- Venice/Siena/medieval Italian hill town style, full of winding lanes and little bridges.
Again in Urban Terror base maps there is Casa, a 'spanish/mexican' village, Abbey 'italian' monastery and Golgatha which is on a slope. And I know one mapper who has started to work on a Venice map but that's a hard mission to finish.
And oddly for a reality mod there's a space station map called Mastermind but it's rather boxy, has none of that swoopy 50tish feel. One map that does have a solid 50tish feel is Crossing 30, but in another style - it's soviet style industrial complex full of agit-prop poster and one of the coolest maps I know of. In similar vein by the same mapper there's Eagle which is based on 'Where Eagles Dare' complete which a Richard Burton radio message. And finally I want to mention Toxic which is a 30tish german industrial place where you'd expect Peter Lorre to step whistling out of a dark corner anytime.
Both the mod and the 3rd party maps can be found at either
http://www.act-of-war.de (Europe) or
http://www.ut.map-depot.com (North America) where you can also find my 'industrial warehouse' map Oildepot but it's sorta turned inside-out set in a cliff valley.
I hope this maps can provide inspiration to make up new stuff as I think it's always a evolutionary process
What I haven't seen is a 'body from the inside' map like that classic Raquel Welch movie Fantastic Voyage
cheers