From the Wikipedia (which has more): "Also known as Surp Asdvadzadzin (the Church of the Holy Mother of God), its construction was started in the year 989, under King Smbat II. Work was halted after his death, and was only finished in 1001 (or in 1010 under another reading of its building inscription). The design of the cathedral was the work of Trdat, the most celebrated architect of medieval Armenia. The cathedral is a domed basilica (the dome collapsed in 1319). The interior contains several progressive features (such as the use of pointed arches and clustered piers) that give to it the appearance of Gothic architecture (a style which the Ani cathedral predates by several centuries)."

As for location, many pictures give gps-coordinates, so you can see for yourself.