A few days ago I found out about the
Tour Divide, an annual mountain biking race that traverses the Continental Divide (Rocky Mountains) from Banff, Alberta, Canada all the way to the Mexican border at Antelope Wells, New Mexico. It's around 2,745 miles (4418 km) and if you add up all the climbs it's like climbing Mount Everest 6.5-7 times.
Not hard enough? Well, you have to do it self-supported, so there's no support vehicle incase you run out of food, no mechanic to fix your bike if you crash, etc. You can buy your own food, stay at a motel if you want to and visit bike shops in the cities you pass, but other than that, everything else is up to you. You are out on your own on trails and paths that few people frequent out in the nowhere. If something happens, you might have to walk 100+ miles to the nearest village. Oh and there are bears, among other wildlife.
There is no prize for winning (nor an entry fee) and you can technically do the route at any time of the year though the official race is during the summer. It takes anywhere between 3-5 weeks to finish (depending on your skill, luck and what you are riding). About half of the participants drop out for various reasons, like mechanical issues, fatigue, dehydration, falls, and just mental exhaustion (riding on your own for days on end).
It's completely crazy, but some people have made it even harder: like riding it on a single speed bike (which is actually an advantage since there's less things to break) and even a fixie.
Here's a
good article about a guy who rode it on a single speed and
another. The most recent article about this race (and how I found about it) is
about this 40 year old who rode it on a single speeder as well.