A celebration of architecture, archaeology, history and nature takes place in Reigate this weekend for the Heritage Open Day.

Between this Friday and Sunday (September 12-14) people can explore caves, historic buildings, fossils, trees, churches, libraries and delve into the town’s past.

The private Holmesdale Natural History Club Museum, at 14 Croydon Road, containing one of the oldest collections of natural history – birds, fossils, insects and botany – local history and archaeology will be open to the public on Saturday and Sunday from 10am to 4.30pm.

The museum, set up in 1857 by William Wilson Saunders a former Reigate resident and naturalist who helped set up Kew Gardens, contains many interesting pieces of local history.

Honorary curator Tracey Parker said: “[William Wilson Saunders] also landscaped the castle grounds.

“Nobody really knows about that so if people want to know more about their local history then they should come along.” Surrey finds officer David Williams will also be at the museum on Sunday, September 14, to identify and record anything of archaeological interest that people have found.

And a heritage tree walk in Reigate to look at the wealth of interesting local trees starts from the Bell Street car park on Friday at 2pm.

The walk will be led by Reigate horticultural manager Paul Donoghue.

He said: “There are quite a few interesting different species there and I will talk about whether they are native trees or if they were introduced.” Call 01737 276226 to book.

At Reigate Priory the attractions will be both the grade I listed building itself which was a family mansion in Tudor times, and an exhibition in the museum open on Saturday and Sunday from 2pm to 5pm.

St Mary’s Church in Chart Lane is not only an impressive 12th century church, but it is also home to the earliest public lending library in England.

Both the church and 18th century Cranston Library, which survives intact in a small chamber above the vestry of the church, will be open on Saturday from 10 until 4pm.

Howard Walden, honourary secretary of the Wealden Cave and Mine Society, encouraged people to visit The Barons’ Cave, not usually open to the public, for an interesting step back in time.

He said: “The Barons’ Cave itself, is part of Reigate Castle, which was probably built by the second earl of Surrey, William de Warrenne, soon after 1088.” Entry to the caves is free on Saturday between 9.30am and 4pm. Find the entrance up the steps by Boots on Reigate High Street.

Barrie Clark, a retired historic buildings architect will be conducting a tour around the historic centre of Reigate starting at 11am at the Red Cross Pub in the High Street.

Mr Clark said many interesting buildings had been lost over the years in Reigate and he intended in his tour to point out what is left and the importance of preserving it.

He said: “We have lost so much so I plan to highlight what buildings of good quality still remain.” Elsewhere in the borough the award winning Pfizer headquarters building in Dorking Road, Tadworth is open on Saturday. Booking is required, call 01737 330715/330701 St Andrew’s Church, Kingswood, a Victorian replica of a 14th century church with interesting stained glass is open on Saturday from 10am to 2pm. The technical research and development department of the BBC is housed in Kingswood Warren, Tadworth, a Victorian gothic country house. Located off the southbound carriageway of A217, the house is open on Saturday and Sunday from 10am to 4pm.

And demonstrations of working horses, traditional woodland management and charcoal making will be held at Banstead Woods, Holly Lane, Chipstead on Sunday from 11am.