Discovered in 1993, the sarcophagus within this whopping Thracian burial mound was carved from a single 60-tonne stone during the 4th century BC. The site continues to puzzle archaeologists – a horse's skeleton has been found, but no human remains – with the biggest mystery being how the granite (not native to the region) was hauled to Shipka. The mound is 3km south of Shipka village. Admission includes entry to the nearby Shushmanets Tomb.
Byzantines damaged many Thracian burial mounds, and Ostrusha Tomb is no exception. Most frescoes have, tragically, been chipped off, but the serene face of a woman on one of the ceiling panels hints at the tomb's past splendour.