According to historical and archaeological data, the oldest monument of national importance in the Municipality of Pirdop are the ruins of the early Christian fortified church in the Elensko area, dating back to the end of the 5th – the first half of the 6th century. The site is included in the UNESCO World Heritage List. The temple is located about 3.5 km northeast of the town of Pirdop. The locality and the river that flows through it are called Elensko and Elenska River, and the ruins of the basilica Elenski monastery or St. Iliya monastery.