Wikipedia
Vätternrundan is a 300 km (186 mile) long recreational bicycle ride held over two weekends in June every year. In 2011, 27 973 cyclists passed the finish line (18 272 on the 300 km course, 3 686 on the 150 km course and 6 015 on the 100 km course). The 300 km course circles Lake Vättern in Sweden, with start and finish in the town of Motala. Approximately 20 per cent of the participants are non-Swedish and in 2011, 37 nations were represented on the course.
For the 2012 event, registration for the main event was limited to a maximum of 23,000 participants.
The cyclists start in groups of 60 or 70, in a two-minute interval between groups. The first group starts at 7.30pm on Friday and the last group starts at about 5.30am on Saturday. In 2010 a new element was introduced as the number of faster cyclists have increased. Groups of cyclists aiming for completing the event in less than 9 hours can start between 9-9.30 am on Saturday morning. In 2011, 720 cyclists took advantage of this possibility. By allowing these cyclists to start later they will have fewer cyclists to pass, thus lowering the risk of incidents and accidents. The course has to be finished by midnight on Saturday.
Vätternrundan is a non-competitive event, and only measures the rider's own time using RF transponders on the helmet (mandatory equipment). An unsorted list of starting times, checkpoints passed and finishing times is published on the website after the event. This type of event is called a motionslopp (recreational ride) in Sweden.
Vätternrundan has nine stops offering food and beverages, and also first aid and free massage. At the finish line riders are awarded a medal and a certificate of achievement, and offered a meal. For safety reasons support cars and personal resupply stops are prohibited. Cyclists returning home by car are prohibited to use their cars within six hours after having finished the event, since fatigue has caused crashes - even fatal ones. The police perform spot checks of drivers after the ride.