Ajina-Tepa is the ruined remains of a 7th- to 8th-century Buddhist monastery on a low mound in the Vakhsh valley. It is not strictly in Hisar but is often combined with a Hisar visit as a longer day trip from Dushanbe. The site itself is now little more than weathered earth walls — the real treasures, including the famous giant clay Buddha, have been moved to Dushanbe.
Even so, the setting is atmospheric: a quiet mound on the steppe, with cotton fields stretching to the horizon. The site is a UNESCO World Heritage tentative listing and one of the easternmost known major Buddhist monastery complexes. Bring water and a hat.