On 18th April 2014, a deadly avalanche killed 13 and left three Sherpa missing on Mt. Everest, the single deadliest day in the mountain's history. To commemorate these men, the Sherpa Fund has created Everest Avalanche Tragedy, a website which includes an interactive simulation of the perilous near-vertical route the Sherpas take up Everest. The poignant simulation includes the sounds of wind and snow as well as the devastating radio recordings from the day of the avalanche. Prepare for a touch of vertigo when you reach the summit.

This kind of immersive digital tour is not always this harrowing. Google Night Walk guides you through the streets of Marseilles, allowing you to go slightly off piste to look at street art or local buskers, while many museums are providing virtual tours. It raises the question, in what situation does the virtual become an adequate replacement for the real thing?