An international team of restorers is racing against time to save the precious mosaics of a giant communist-era building sat atop a mountain peak in Bulgaria.
The "UFO-shaped" Monument House of the Bulgarian Communist Party was built between 1971 and 1984, to celebrate the history of the party.
The memorial on Buzludzha mountain is one of the most spectacular projects of the Bulgarian communist regime.
Its mosaics are made of more than two million pieces and cover an area of around 1,000 square metres.
But, after the fall of the Soviet Union, the construction was abandoned and its works of art severely damaged by vandalism.
Furthermore, after the dome collapsed, the mosaics remained completely exposed to the weather.
"Securing the most endangered mosaics is a very challenging task because all the mosaics have different materials and it's a task that hasn't been done in Bulgaria so far," Dora Ivanova, the project leader of the restoration, told Euronews.
"We are very happy to work in an international team. We are working with 18 restorers from four European universities and several NGOs. They come from Germany, Greece, Switzerland and Bulgaria."
The building is still publicly owned, but the restoration works are privately funded and have cost €200,000 so far.
The memorial still attracts tourists and urban explorers.
Find out more by watching the full report in the video player, above.