Next to climate change, nuclear waste storage is one of the biggest generation-spanning issues facing the world. The stakes are high; world powers like the US and the U.K get a fifth of their power from nuclear plants, while in France the share is 40 percent. This reliance makes the need for safe and sustinable storage obvious.

But it’s a country with merely four plants that is pioneering long-term storage: Finland, according to Nordic Business Insider.

Onkalo, a “massive underground tomb” in Finland, has recently broken ground to store more than 6,500 tons of waste for at least 100,000 years. The Wall Street Journal has written an extensive article about the groundbreaking waste repository.

“I would congratulate the Finns on having made the progress to get to this point. [..] They’ve gotten further than anyone else has.” said Peter Swift, a senior scientist at a Lockheed Martin -operated U.S. laboratory to WSJ.

Situated on an island just outside the Finnish coast, Olkiluoto is home to two of Finlands four nuclear plants; while a fifth one, the Olkiluoto-3 is under construction. And soon, the area will have its underground storage facility in the form of Onkalo.

Since 2004, Finland’s two main nuclear-power companies, Fortum and Teollisuuden Voima (TVO) have been digging into ancient bedrock, in order to create deposition tunnels leading 420 metres below ground.

The nuclear-waste storage methods being used today are seen as inadequate in the long term, providing at best decades of safe storage; in addition to the added risks of storing waste on ground level.