A large percentage – around 95% – of the ocean has not been explored by humans, according to UNESCO Ocean Literacy. And in that 5% we have found some weird and wonderful things, such as a whole city sitting beneath the sea which could reveal how life on Earth began (Picture:D. Kelley/ M. Elend/UW/URI-IAO/NOAA/The Lost City Science Team)

What is the Lost City?

It’s not a lost city in the traditional sense but instead it is a field of mineral towers just dubbed as the Lost City. It is, in fact, the oldest known hydrothermal system in the ocean. Researchers believe that its extreme conditions mirror how the early Earth was like, and could offer clues on how the first life forms may have emerged (Picture: Deborah Kelley, University of Washington)

Where is the Lost City?

The vast mineral towers sit more than 2,300 feet beneath the water on the slopes of an underwater mountain in the Mid-Atlantic Ridge, just south of the Azores islands, near Portugal. This area marks the boundary between tectonic plates and is a hotspot for geological activity, and the ridge is a massive underwater range that runs through the ocean (Picture: IFE, URI-JAO, Lost City science party, and NOAA)

How old is the city?

Very old. The city was first discovered in 2000, and is thought to be the longest-living venting environment found in the ocean. It’s thought to be around 120,000 years old, an has been reacting with seawater to release hydrogen, methane and other dissolved gases into the ocean (Picture: IFE, URI-JAO, Lost City science party, and NOAA)

What does the city look like?

The mineral vent looks large, with cracks and vents that feed the local community. It has towering spikes, some of which are nearly 200 feet tall, which is formed by a unique geological reaction known as serpentinization, which is where the seawater reacts with mantle rock deep beneath the seafloor (Picture: Tomaso Bontognali, Susan Lang, and Gretchen Früh-Green)

Researchers have recently revealed a record-breaking recovery of mantle rock – of around 1,268 metres long. It’s thought that the sample could help provide evidence on how life on Earth emerged billions of years ago under conditions found in the minerals. The vents produce hydrocarbons, organic compounds made from carbon and hydrogen, which are considered the building blocks of life (Picture: IFE, URI-JAO, Lost City science party, and NOAA)

While microbes inside the rocks live in total darkness where they rely on methane and hydrogen as their only fuel. But on the outer surfaces, the towers are home to an abundance of snails and crustaceans. Larger animals such as crabs, shrimp, sea urchins, and eels are rare, but still come to visit (Picture: IFE, URI-JAO, Lost City science party, and NOAA)