Welbeck Abbey
Only small parts of the Welbeck Abbey Estate are open to the public which is a pity as it is an impressive place. You can visit the garden centre in the old walled gardens and the Harley Gallery. There is a bridleway(see walk 2 below) that takes you across the lakes and along the side of one of the famous tunnels.
The Welbeck Abbey wikipedia entry carries more details.
William John Cavendish, 5th Duke of Portland (1800-79), was the eccentric owner of the Abbey. Living as a recluse in a small suite of rooms in the massive abbey, he employed a team of hundreds of workmen to excavate a series of underground rooms. They include a 53 m (174 ft) long ballroom and a 76 m (250 ft) long library, along with a series of tunnels claimed to be wide enough to drive a horse and carriage. Within the complex, food was delivered to the duke on miniature railways. See the entry for Welbeck Abbey in Nottinghamshire History.
Walks
Welbeck walk 1 Leisurely – 3.6 miles (5.7km) Through the well-kept woods and along a farm track from Welbeck tunnel entrance at South Lodge. Good views on the way of Worksop Manor and Worksop with the spire of St John’s Church prominent. Walk back across the fields, then down to the lake and back. Recommended but poor road to it
Creswell Crags walk 2 Moderate – 9.5 miles (15.2). Most of the walk is on tracks, but fields can be muddy after heavy rain. Find out about the eccentric Duke of Portland and his buried coach roads before going. Recommended
Worksop walk 2 Moderate – 10.3 miles (16.5km). A long varied circuit through outer parts of Clumber and Welbeck. Good views of Worksop Manor, Manor Farm and Worksop with the spire of St John’s Church prominent. Recommended but difficult crossing across Worksop bypass – need patient and wait for gap.
Sherwood Forest Information 