Road running is the sport of running on a measured course over an established road. This differs from track and field on a regular track and cross country running over natural terrain. These events are usually classified as long-distance according to athletics terminology, with races typically ranging from 5 kilometers to 42.2 kilometers in the marathon. They may involve large numbers of runners or wheelchair entrants. The four most common IAAF recognized distances for road running events are 5K runs, 10K runs, half marathons and marathons. Running on the road is an alternative surface to running on a trail, track, or treadmill. For many people looking to participate in running as an activity or sport, there are multiple opportunities that can be found on the road. Road running is one of several forms of road racing, which also includes road bicycle racing and motor vehicle road racing. IAAF The international governing body for road racing is the IAAF. The IAAF aims to set the standards for competitions by ensuring that all participants are drug-free and that all equipment used is legal. The IAAF measures each race course to give it an IAAF certification rating. Once a race course is certified, the course can be counted for different records or rankings. Courses Racecourses are usually held on the streets of major cities and towns but can be on any road. The IAAF recognizes eleven common distances for road races that are eligible to be counted for records if they meet the eligibility criteria: , , , , , half marathon (21.0975 km or 13.1 mi), , , marathon (42.195 km or 26.2 mi), , and . The 24-hour run is also recognized. Of these, the 5K, 10K, 25K, 30K, half marathon, marathon, and 100K are distances that are recognized for world records. Some major events have unique distances. The Fifth Avenue Mile in New York City, United States is ; the "Round the Bays" run in Auckland, New Zealand is ; the Falmouth Road Race in Falmouth, Massachusetts is ; the Manchester Road Race in Manchester, Connecticut is ; "City to Surf" in Sydney, Australia is ; Honolulu's "Great Aloha Run" is ; the "King Island Imperial 20" is long; and the "Charleston Distance Run" in Charleston, West Virginia is . Participation Most road running events are open to the general public. Participants of varying running ability are participants. It is