Created: 2004
Where: Teddington, UK
Scale: Over 570 locations in 20 countries with over two million runners

Based on the simple principle - weekly, free, 5km for everyone, forever - Parkrun organises volunteer-led runs in parks around the world. Founded by Paul Sinton-Hewitt in 2004 and originally named the Bushy Parkrun, the first event had 13 runners and three volunteers.

Advancements in technology led to the shift from paper to the online registration and barcode system Parkrun is now known for, making it significantly easier for them to scale.

One of the key factors of Parkrun's success is inclusivity, with runners of any ability - from club runners to wheelchair users, and the elderly - all encouraged to take part. This combination of a simple concept and low barriers to entry, has resulted in Parkrun becoming one of the biggest sporting events in the world, with millions of runners pounding the pavements in over 20 countries.