Sport Relief Mile Events are taking place all over the country on Saturday.
Scotland, Wales and Ireland are all staging high-profile events, while every BBC region in England will also boast an occasion of their own.
In addition, more than 100 events have been organised in towns up and down the country.
Milers will tackle their event in one of two ways, designed to cater for those who want to take the event seriously and those who simply want to enjoy the experience and go the extra mile to help tackle poverty around the world.
The Time Trial Mile is for those serious enough about their running to aim for a personal best time over the distance.
The Freestyle Mile offers everyone the chance to cover the mile at their own pace - and in any way they choose.
The Mile Events are being staged nationwide to celebrate the 50th anniversary of Roger Bannister's four-minute mile.
The events will help Sport Relief in its bid to top the staggering £14m raised from the inaugural event in 2002.
But the Mile Events are just part of a series of a massive day of sporting celebrations on Saturday, culminating in a five-hour live evening show on BBC 1.