Inside the underground tunnel where no humans will be able to visit for 100,000 years

There's a place which no humans will set foot in for a whopping 100,000 years in what will mark a world first.

To put that timeline into comparison, 100,000 years ago wooly mammoths still roamed the earth during the ice age while the first humans migrated in the harsh conditions, with many dying.

What the world will look like 100,000 years in the future is unknown - mankind may have left Earth already by then.

But if we have stuck around then we'll finally be able to enter the underground tunnel in Finland where no humans can go for about 4,000 generations.

The northern European country, that borders Sweden and Norway as well as Russia, has built the world's first geological tomb where it plans to bury spent nuclear fuel.

While it sounds terrifying, the nation has plaudits from around the globe claiming Finland to be 'a model for the entire world' for the sustainable storage of nuclear energy.

"A tour at Onkalo, which lies 450m (1,480ft) below the ground, to see tunnels hewn in the living rock to store highly radioactive waste for 100,000 years, suddenly makes me nervous," writes BBC journalist Erika Benke who was offered a walk around the tomb.

A deposition hole, approximately 8m deep and 1.75 m in diameter, is pictured in the Repository in ONKALO, a deep geological disposal underground facility designed to safely store nuclear waste (JONATHAN NACKSTRAND/AFP via Getty Images)

In 2025, it will be closed off to the world and no humans will be allowed inside it for 100,000 years.

It is the brain child of the country's waste management organization Posiva, which explained its plans to place the spent fuel in water-tight canisters which would then be placed in the Onkalo geologic repository.

Located in southwestern Finland, it can be found near to the Olkiluoto nuclear power plant.

Benke explained how she had to pass through a turnstile at a security gate before hopping into a car driven by her guide.

"It takes 15 minutes to drive down to Onkalo's service station which lies 437m (1,430ft) below the ground. As the 4.5km-long (2.8 mile) tunnel begins to snake down, we see a standard traffic sign for a 20km/h (12mph) speed limit. There are also green signs on the tunnel wall at regular intervals indicating how far we are from the surface," she writes.

A car drives in the access tunnel of Posiva's spent nuclear fuel repository Onkalo back in 2017 (Antti Yrjonen/NurPhoto via Getty Images)

Benke went on to explain how the tunnel was narrow, only enough space for one car, and how the the nuclear waste canisters 'will arrive at the service area in a lift running straight down from the encapsulation plant on the surface'.

Adding: "When the spent fuel starts being stored here, canisters will be lowered from this lift landing area further down to a deposition tunnel where they'll be picked up by robotic vehicles to take them to vertical deposition holes – their final resting places.

"We're shown a demonstration deposition tunnel. Its entrance is a lot darker than the service area and the floor is uneven and wet, muddy in places. The walls are bare bedrock that glints in the torchlight."

And I guess from next year, the rest will remain a mystery...