Paul Hoover holds balloons as he poses for a photo before taking part in his 100th parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Runners compete in the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Competitors wait near the start of the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Runners compete in the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Runners cross Hampstead Heath in north London during a parkrun event on Saturday Sept. 14, 2024. (AP Photo/Lucy Nicholson)
Runners compete in the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Competitors listen to the briefing before the start of the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Bar code tags used by competitors are collected at the end of the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Competitors show a bar code after competing in the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
A runner shows off a parkrun wrist band after completing the 5 kilometer (3.1 mile) route in Hampstead Heath in north London on Saturday Sept. 14, 2024. (AP Photo/Lucy Nicholson)
Wendy Stokes, one of the core organisers of the Bushy Park parkrun, gives her briefing before the start of the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Runners and their dogs, compete in the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
Runners compete in the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)
A woman waits with two dog as she watches runners compete in the parkrun event in Bushy Park, southwest London, Saturday, Sept. 28, 2024. (AP Photo/Alastair Grant)