Take a tour underneath a GLACIER: Man-made tunnel that will reveal how icy rivers work to open in 2015 Icecave Iceland is due to open in the spring 2015 and will enable tourists to take in blue ice at the heart of the LangjÃ¶kull glacier nearÂ Reykjavik A CGI video offers a sneak peak of the underground tourÂ Engineers are currently carving the 1,640 foot (500 metre) long tunnel It shows layers of Â subtlyÂ colouredÂ ice, showing how the glacier formedÂ Visitors flock to Iceland to see its impressive geysers, Blue Lagoon and meandering glaciers. And soon there will be a new way of taking in the countryâ€™s second largest ice cap near Reykjavik â€" from an underground tunnel dug deep beneath the dense ice. Icecave Iceland is due to open in the spring of next year and will enable tourists to take in blue ice at the heart of the LangjÃ¶kull glacier and understand how it formed. But for now, there's a video enabling people to take a virtual tour so they have an idea of what to expect. A screen shot is pictured A CGI video has been released to let people take a tour from the comfort of their sofa. It gives potential visitors an idea of what to expect, including tunnels, underground rooms and lit caverns. Engineers are currently carving the 1,640 foot (500 metre) long tunnel beneath the glacier and are installing lights to best show off the layers of ice. Engineers are currently carving the 1,640 foot (500 metre) long tunnel (pictured) beneath the glacier and are installing lights to best show off the layers of ice. A geologist is on hand to advise on the operation LangjÃ¶kull glacier (marked with a B) is located near Iceland's capital, Reykjavik. It's theÂ is the second largest ice cap in Iceland with an area ofÂ 953 square kilometres The glacier (pictured) is roughly parallel to the direction of the country's active volcanic zone, running north-east to south-west. It is about 31 miles (50 km) long and nine to 12 miles (15-20km) wide If you stare into deep crevasses in glaciers - or take a tour beneath one - you will notice that the ice is blue. Snow, and ice near the surface, is white because the full spectrum of light is scattered and reflected. The ice looks blue because it is so dense, with no bubbles to scatter visible light. In ice, the absorption of light at the red end of the spectrum is six times greater than at the blue end. So as light travels into the glacier, red light is gradually lost. A lack of reflected red wavelengths mean that we see the ice as blue. Glacial ice is made up of compacted snow that has fallen over thousands of years. Visitors to the attraction will see stripes of subtly different coloured layers of ice that represent different periods of snowfall. The layers can be analysed to tell experts about the weather conditions at the time the snow fell. Whiter layers formed when the weather was particularly cold, because air was trapped within the ice crystals, which is reflective. Layers that are darker or bluer in colour were created by snowfall in warmer or wet conditions when little air was trapped in the snow. The weight of the snow build-up compressed the layers and the air trapped within them, causing ice at the heart of a glacier to appear a brilliant blue. Icecave Iceland says the attraction will offer a â€˜once in a lifetime adventure, to explore around, on and within the mighty LangjÃ¶kull glacier, where they will be able to see, the beautiful blue ice that lies at the heart of the glacier,â€™ when it opens.Â Tourists visiting the attraction will see large caves beneath the glacier (pictured) and will also be able to sit inside man-made rooms with ice furniture, according to the video tour People embarking on the tour will travel up the glacier to the ice cave, on eight-wheel drive super trucks. â€˜Exclusive groups, will experience the thrill of descending beneath the ice cap glacier, learning interesting facts about glaciers, and eventually reaching the beautiful and stunning blue ice, that lies at the heart of the glacier,â€™ it says. Tours will run between March and October depending on the weather. While there are other natural caves in Icelandic glaciers, they are seasonal, forming in warmer months and lasting in winter.Â Visitors to the attraction will see stripes of subtly different coloured layers of ice (pictured) that represent different periods of snowfall. The layers can be analysed to tell experts about the weather conditions at the time the snow fell Ice Cave Iceland says the attraction will offer a â€˜once in a lifetime adventure, to explore around, on and within the mighty LangjÃ¶kull glacier (pictured from above), where they will be able to see, the beautiful blue ice that lies at the heart of the glacierâ€™