In early 2017, the world was surprised when footage of a coral reef in the Amazon River was released. According to Fabiano Thompson, one of the researchers who announced the discovery of the reef in 2016, it's a place "where the textbooks said there shouldn't be one."

The video footage is slow moving, but it doesn't negate the unfiltered beauty of the reef. If anything, it gives the viewer more time to soak in the surprising nature of the discovery. Researchers first stumbled onto the reef in 2012 after hearing rumors about it.

Initially, researchers believed the reef ran between 164 and 328 feet deep and spanned 3,668 square miles, or about three times the area of Rhode Island.

However, a new study in April 2018 shows the reef is six times larger and deeper than previously thought. Researchers also discovered the reef system is compromised of reef platforms, reef walls, rhodolith beds and sponge bottoms. Only 5 percent of the reef has been explored though — leaving room for even more discoveries of what exactly is living there.

The area is murky and prone to strong currents — another reason the deep-diving vehicle that shot the video is moving slowly — but plenty of marine life, including a sponge that weighed as much as a baby elephant, thrives on and around the reef.

Oil companies have been eyeing the area because it's estimated there could be between 15 and 20 billion barrels of oil in the area. Greenpeace, which supplied the footage of the reef, has mounted conservation efforts to keep the reef safe from drilling and potential oil spills.

Editor's note: This article has been updated since it was originally published in February 2017.