The world's oldest temple, dating back around 12,000 years, is located on Göbekli Hill in Turkey's province of Sanliurfa. The name means "hill with a navel".
The temple stands around 15 meters in height and 300 m in diameter, and located on a 800m high hill upon which a single tree stands.
The site is located 15-km northeast of Urfa on the top of a range of limestone-hills that forms the south-eastern extension of the Taurus-mountains.

IMAGE (http://img301.imageshack.us/img301/2874/gbeklitepeqd3.jpg) (66kb, 800 x 494)

Latitude: 37°13'25.69"N Longitude: 38°55'18.81"E

What type of religion was practiced here?

What type of religion was practiced here?

i dont know.
but, I was going to post this into the astronomy section, as i figured that it was a astronomical or solar based religion.

Wikipedia has a bit about it.

The excavator, Klaus Schmidt, has engaged in some speculation regarding the belief systems of the groups that created Göbekli Tepe, based on comparisons with other shrines and settlements. He assumes shamanic practices and suggests that the T-shaped pillars may represent mythical creatures, perhaps ancestors, whereas he sees a fully articulated belief in gods only developing later in Mesopotamia, associated with extensive temples and palaces. This corresponds well with the Sumerian tradition of an old belief that agriculture, animal husbandry and weaving had been brought to humankind from the sacred mountain Du-Ku, which was inhabited by Annuna-deities, very ancient gods without individual names. Klaus Schmidt identifies this story as an oriental primeval myth that preserves a partial memory of the Neolithic.

Read more (http://en.wikipedia.org/wiki/G%C3%B6bekli_Tepe)

BTW, they give the wrong location. Can someone change it?
(i can`t for some reason)