The South Downs Way – this is what Wikipedia says about it.

The South Downs Way is a long distance footpath and bridleway.^[2] The trail has about 4,150 metres (13,600 ft) of ascent and descent making it a challenging route.

The undulating path begins in Winchester and moves past Cheesefoot Head, the towns of Petersfield and Arundel, the village of Steyning, Devil's Dyke viewpoint near Brighton, and miles of chalk downland, finally ending in Eastbourne. Several youth hostels are along the route to accommodate walkers. It also passes Birling Gap, a beach area with hotel and restaurant. At Rodmell on the trail, Virginia Woolf drowned herself in the River Ouse in 1941.

Much of the South Downs Way is on high chalk downland and the views are dramatic. The Way is solely within the Sussex Downs and East Hampshire Areas of Outstanding Natural Beauty, soon to become the South Downs National Park. There is plenty of historic interest along the way. Without exception it is a very well maintained and signposted route. While it crosses various villages for provisions much of it is surprisingly isolated and quiet considering the density of the population in south-east England.

It can be walked in about a week while a horse rider or cyclist would take two or three days. It is closed to motorised traffic along the route and this rule is generally observed.

Various events are held along the route; the most popular of which is the British Heart Foundation's annual Randonee. Part or all of the 100 miles is cycled to raise funds for heart disease, the fastest times are sub 8 hours with most riders taking under 14 hours.