In pictures: Siberia's Ice Marathon

If you thought running the London Marathon this weekend was tough, try tackling the sub-zero Siberian version across a frozen lake.

The International Lake Baikal Ice Marathon offers competitors the unique opportunity to race across the surface of the world's largest, oldest and deepest lake.

During this extraordinary event, which starts with a shot of vodka to appease the the spirits of the Great Baikal, runners race along the surface of Lake Baikal in pre-chiseled tracks though fields of 'hummocks' - small hills of ice rubble - that are scattered on the lake's surface.

It's a gruelling, bone-chilling, physical exertion that photographer and writer Ed Graham knows well, having participated in the 2013 Ice Marathon earlier this year.

Graham first encountered the Lake Baikal race over a year ago during his first journey on the Trans Siberian Railway and his love of extreme travel persuaded him to sign up for the marathon.

He writes about his experience in his blog, The Polar Route: "I said "screw it" and I signed up for it anyway, knowing I could always back out. Soon after, one of my best friends and a good travel buddy unexpectedly passed away from cancer diagnosed just two weeks before he died."

"He was a guy who always lived life to the fullest both at home and on the road, and his grand adventures had continually inspired me to do the same. Attempting this race would be my own version of living a full life, and I knew then that I had to complete it."

Graham completed the marathon in March and managed to take some incredible pictures while he was at it.

Have a look at his astonishing photographs of ice gems glowing in the sunset and the vast, black-ice expanse of the frozen Lake Baikal below.

Have you signed up for a marathon this year or do you fancy taking on Siberia's Ice Marathon after seeing these pictures? Tell us below.

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