Pictured: The world’s longest underground slide, which is hidden inside a MOUNTAIN in Graz in Austria

Thrill seekers – grab your ticket… to slide.

This is the tallest underground slide in the world – and the second tallest overall – a structure that stands a whopping 64 meters high and 175 meters long, with riders reaching speeds of up to 30 km/h during the 40 meters. second descent.

Intriguingly, the attraction, called the Schlossberg Slide, is completely hidden within the tree-covered Schlossberg, which at a height of 473 meters (1,551 feet) dominates Austria’s second largest city, Graz.

The hill, called ‘castle hill’ in German, was once strongly fortified, but the defenses were destroyed by Napoleon in the 19th century. It is now a popular public park with extensive views of the city.

The Schlossberg Cable Car is a popular way to reach the top, along with a glass elevator that the slide is partially wrapped around (visitors can also walk to the top). The entrance to the lift – and the exit to the slide – are located in a tunnel system that served as an air raid shelter during the Second World War.

The Schlossberg slide in Graz, Austria, is the tallest underground slide in the world – and the second tallest overall

The slide is 64 meters high and 175 meters long, with riders reaching speeds of up to 30 km/h during the 40-second descent

The slide is 64 meters high and 175 meters long, with riders reaching speeds of up to 30 km/h during the 40-second descent

Schlossberg Slide is completely hidden within the tree-covered Schlossberg, which at a height of 473 meters (1,551 feet) dominates Austria's second largest city, Graz.

Schlossberg Slide is completely hidden within the tree-covered Schlossberg, which at a height of 473 meters (1,551 feet) dominates Austria’s second largest city, Graz.

Both adults and children can experience the slide, but before they let themselves slide down, there are a few things to keep in mind.

According to the slides websiteVisitors must be taller than 1.3 meters (4.2 ft) and must not be under the influence of alcohol while driving.

Each person is given a sliding mat and must position themselves with feet pointed down and arms and elbows close to the body.

The Austrian slide was well received on Tripadvisor and received a rating of four out of five stars based on 45 reviews.

The slide was well received on Tripadvisor and received a four out of five star rating based on 45 reviews

The slide was well received on Tripadvisor and received a four out of five star rating based on 45 reviews

One visitor called it a “great way to get down the mountain,” while another person wrote, “It’s a great break from the sights and old European buildings.”

For those who don’t like thrills, there are plenty of other attractions on the Schlossberg, including one 4D cinema experience.

The Flight Graz 4D takes visitors on a 10-minute virtual tour of Graz using 4D motion cinema. It is described as a ‘scenic escape’ from the city with immersive effects including movable seats, wind and fog.

At the top of the hill, visitors can stroll through the gardens, admire sensational views over the city and view the hill’s iconic clock tower, called the Uhrturm, which was built in the 16th century as part of the city’s fortifications.

Tickets for the slide cost €6 (£5.10) per person and can be purchased online at www.schlossbergrutsche.at/?LNG=en.