In addition to the route achievement, watt and distance badges, Zwift has three challenges: Climb Mt. Everest, Ride California and Tour Italy.
These challenges are essentially awarded by commitment to the platform, by regularly showing up and riding.
The Climb Mt. Everest challenge is achieved by climbing 8,850 metres and so those who don’t shy away from the hillier routes are going to work towards this challenge a lot quicker than those you find they always choose a flatter course. Plus, if you keep on going to 50,000, you’ll unlock the ‘Tron bike’.