Archaeologists excavating in the Hamadan province of Iran have made an astonishing discovery – the remains of an ancient underground city.

The excavation site is located close to the city of Samen, in Iran's Hamadan province. It is located some 400 km from the Iranian capital, Tehran.

The city consists of underground tunnels connecting at least 25 rooms. Archaeologists have discovered the remains of 60 people in nine rooms, and are still working on excavating the rest of the site.

Ali Khaksar, head of Iran's Organization of Cultural Heritage, Handicrafts and Tourism in Hamadan province, told Khabar Agency, a media outlet, that the underground settlement is believed to be around 2,000 years old.

The discovery is one of several exciting findings by Iranian archaeologists in recent months. Last month, archaeologists discovered underground living quarters carved into a mountain in central Iran dating back to the 12th century.

In February, an excavation in southern Iran led to the discovery of an ancient observatory which is believed to date back to the reign of the Sassanian dynasty from 224 to 651 CE.