Listed in the Guinness Book of Records as the highest marathon in the world, this marathon is noted as one of the toughest in the world as well. Although the race itself is all downhill, runners will have to deal with cold temperatures and very little air in the high elevation. In fact, all participants are required to be in Nepal for 3 weeks prior to the beginning of the race so they can acclimatize to the high altitude. The 3-week stay involves sightseeing tours of Kathmandu and a 14-day ascending journey to the starting point. Reaching 18,200 feet, runners perform the entire race downhill, including steep icy spots that have danger lurking around every turn. You can expect snow and ice at the top of the route, as well as rocky, craggy terrain all the way to the end. Participants will finish at the Sherpa town of Namche Bazaar at 11,300 feet. Along the way, you will definitely be treated to some of the most spectacular views available on earth. The race began in 1987 and was held bi-annually until 2003 when organizers decided to make it an annual event. The Everest Marathon receives applications from long-distance runners all over the world. Many want to try it just for the bragging rights.