Apollontempel am Hundstalsee, Stone temple at Hundstalsee lake, Tyrol, Austria

The Apollontempel am Hundstalsee is a stone structure in the Tyrolean Alps, built directly above the lake it is named after at around 2,289 meters (7,510 ft) elevation. It features a walkable dome and two towers, all assembled from natural stones without mortar.

The structure was started by artists Robert Tribus and Heinz Triendl in 1986 and took two decades to complete, finishing in 2006. Throughout that period, the Austrian Federal Forests raised repeated legal objections that interrupted the work on several occasions.

The temple honours Apollo, god of the arts, as conceived by Robert Tribus, a connoisseur of Greek mythology, and Heinz Triendl, who knew the Hundstalsee as a mystical place. A colonnade still under construction is to be flanked by seven stone cairns representing the Seven Sages of Greek myth. The artists' Apollonian Manifesto of 1990 gathered written solidarity from well-known artists.

The temple stands at 2,289 m on the shore of the Hundstalsee in the Inzing municipality; the long approach and often difficult weather allowed building on only about 30 to 40 days a year. A footbridge leads from the stair portal, 1.3 m high and 0.9 m wide, into the lake. An avalanche wall protects the rear of the structure.

In the winter of 2020/2021, a rockfall almost completely destroyed the orographically left tower, which was then rebuilt. The artists had already filled the interior with stones in 1997 to avoid the term 'building'; these stones were later reused for the footbridge into the Hundstalsee.