Since the beginning of human life, we’ve been trying to figure out how we got here. Now, the answer to that question has gotten clearer.

On September 1st, 2016, scientists discovered the oldest physical evidence of life on earth in Greenland. 

According to CNN, the fossils date back 3.7 billion years, 220 million years older than any other fossils previously found. Although previous studies suggest life on Earth dates back nearly 3.8 billion years, this is the first time those findings are supported by physical evidence. The researchers published their findings in a journal on Nature.com.

The fossils are believed to be stromatolites, which are mound-like structures produced by photosynthetic bacteria.

Allen Nutman, a professor at the University of Wollongong in Australia, and one of the co-authors of the research, shared his thoughts with CNN.

“For the first time, we can actually see an environment in which early life flourished,” Nutman said.

Nutman was part of a group of Australian scientists researching the Isua supracrustal belt in southwestern Greenland, which are among the world’s oldest rocks.

What made the discovery surprising, according to Nutman, was the fact that the fossils only appeared after a block of snow gradually melted. Nutman said there was a “diminishing possibility” that older fossils would ever be found, as rocks from that period are very rare.

“We noticed that an area that for decades had been covered by a snow patch, even in the middle of summer, was free of snow. We walked over and immediately realized what we were looking at,” Nutman said.

Dr. William Martin of Henrich Heine University was pleased with the results of the research.

“If they really are of biological origin — and I think they’re convincing — then it’s interesting in two ways. One, it would be the oldest fossils we have. Number two, they’re almost certainly photosynthetic…that would really put an ancient date on photosynthesis,” Henrich said to CNN.

It isn’t often that a major discovery is made in the science industry, as Nutman explained before, but this recent find has provided clues as to when life began.