Ultrmarathon events, or ultras, are any running races with a distance beyond the standard marathon length of 26.2 miles (or 42.2km). The most common ultra distances are 50k, 100k, 50 miles, or 100 miles, but each event is unique in terms of distance and terrain. The International Association of Athletics Federation recognises world records at ultramarathon events that have a distance of 100km. There are even 24hr ultramarathons, where the distance is unlimited, or multiday ultras, where the distance can extend beyond 1000km. For Londoners whose running itch isn't quite scratched by the London Marathon, there are two ultras available in the UK's capital. The Thames Path 100 is a famously scenic option and the London to Brighton Challenge is known for its friendly crowds and competitors. Both these events test even the most seasoned athletes without having to travel far from home, so they provide a great introduction to the ultra community.
