Our world is still ripe for exploration. Just last year, scientists discovered a previously unknown coral reef located at the mouth of the Amazon River. 

They have now delivered a bunch of images showing this never-before-seen biome, following a collaboration with an expedition by the Greenpeace ship Esperanza.

The system of corals is absolutely huge, covering an area larger than São Paulo or London. It consists of a patchy strip that stretches for 1,125 kilometers (700 miles) in length, from a few miles off the coast of French Guyana to the Brazilian state of Maranhão. The researchers documented the Amazon Coral Reef in a mini-submarine (below) launched from the Esperanza, around 100 kilometers (62 miles) off the Brazilian coast.

This is a particularly unusual spot for a coral reef, since they are usually only in salty waters with clear access to sunlight, not a muddy river mouth like this one.

“This reef system is important for many reasons, including the fact that it has unique characteristics regarding use and availability of light, and physicochemical water conditions," Nils Asp, a researcher at the Federal University of Pará, said in a statement. "It has a huge potential for new species, and it is also important for the economic well-being of fishing communities along the Amazonian Coastal Zone."

^{© Marizilda Cruppe / Greenpeace}

Unfortunately, oil companies Total and BP are eyeing up the nearby area that is thought to hold between 15 and 20 billion barrels of crude oil, according to Greenpeace.

“We must defend the reef and the entire region at the mouth of the Amazon River basin from the corporate greed that puts profits ahead of the environment," added Thiago Almeida, campaigner at Greenpeace Brazil. "One of Total's oil blocks is only eight kilometers from the reef, and environmental licensing processes are already under way."

You can check out the series of photographs of this beautiful new world below.

^{© Greenpeace}

^{© Greenpeace}

^{© Greenpeace}

^{© Greenpeace}