A 75-year-old Soviet "floating city" is slowly crumbling into the sea, like a modern-day Atlantis. Neft Daşları or "Oil Rocks" was constructed in 1949 by Soviet leader Josef Stalin off the coast of Azerbaijan in the Caspian Sea.

The rig originally consisted of just one drilling well and a small house for accommodation. In the following years and decades, Neft Daşları became home to nearly 2,000 wells and around 320 production sites. These were connected by more than 100 miles of bridges, and over 60 miles of oil and gas pipelines. 

A small city grew up around the rig, consisting of accommodation blocks, a theatre, shops, medical facilities, a football pitch and a heliport.

The city's massive bases were built on shipwrecks and roughly 5,000 workers lived and worked on the mega-rig at its peak.

Neft Daşları has produced nearly 180 million tons of oil in its 75-year lifespan, pumping out a record 7.6 million tonnes at its height in 1967.

However, the oil rig hit hard times as the Soviet economy declined, with buildings and other installations gradually falling apart due to a lack of maintenance.

The decline continued at pace after the collapse of the Soviet empire, and by 2012 only around 20 miles of roadways were still in use.

Documentary filmmaker Marc Wolfensberger visited the rig in the late 1990s, before making his acclaimed film “Oil Rocks: City Above the Sea" in 2009.

"It was beyond anything I had seen before,” he told CNN, adding it was like “a motorway in the middle of the sea," stretching out “like an octopus.”

The sea-city today is still home to some 2,500 people with experts claiming around 30 million tons of oil could still be extracted from the seabed. However, the city is slowly sinking, prompting many residents to relocate to the mainland. 

A spokesperson for the national oil company SOCAR said that Neft Daşları remains “an active asset with a unique role” for Azerbaijan.

Azerbaijan is one of the major oil and gas producers in the world, producing some 33 million tonnes of oil and 35 billion cubic meters of gas in 2022.

The country borders the Caspian Sea, which is rich in fossil fuels. These fuels have helped to drive and grow Azerbaijan's post-Soviet economy.