Tiwanaku Semi-subterranean Temple, Pre-Columbian temple in Tiwanaku, Bolivia.

The Tiwanaku Semi-subterranean Temple is a pre-Columbian structure with a sunken rectangular courtyard, its stone walls decorated with carved heads and intricate monolithic carvings. The design shows careful planning with multiple levels and detailed stonework throughout.

Built probably during the Late Formative period, the sunken court is among the oldest structures at Tiwanaku. In 1932 Wendell Clark Bennett's test pit in its northern half uncovered the 7.3 m red sandstone Bennett Monolith and two smaller stelae, likely still in situ. Carlos Ponce Sanginés and CIAT fully excavated and reconstructed the temple between 1960 and 1964.

The carved stone heads on the temple walls suggest the importance of ritual and spiritual practice in this ancient Andean society. These faces indicate how sculpture played a central role in religious life and ceremony.

The sunken courtyard is entered by a monumental staircase on its south side; the surrounding walls stand about 2 m high, so the floor lies below the level of the Kalasasaya platform. The court measures roughly 26 by 28 m. The site sits at high Andean altitude, so allow time to acclimatise before walking the ruins.

The courtyard walls are studded with 175 carved human heads of volcanic tuff, no two alike. Most were found still set in the masonry or close to its base, but on the north side many lay scattered up to 6 m from the wall. A basalt block with Tiwanaku iconography was also found here, now in the Museo Lítico de Tiwanaku.