People are being invited to find out ore about the waterways at Apsley Lock on Sunday, January 12.
Locks 65 and 66 at Apsley on the Grand Union Canal in Hemel Hempstead will be drained to allowed visitors to go down inside the chambers where Canal and River Trust volunteers will be on hand to give tours.
There will also be children’s activities, fishing, boat trips and guided tours of the historic Frogmore Mill between 10am and 4pm.
The usually hidden waterways history is being opened up to the public as part of the trust’s winter schedule of works to repair and restore hundreds of waterway structures as part of a £45 million programme stretching over 2,000 miles of canals and rivers and sponsored by Kier.
The Apsley locks are accessible via foot from Ebebrns Road. There is parking available at Sainsbury’s, London Road, and access to the towpath is via the car park.
Senior waterways manager Jeff Whyatt said: “Most people will have walked past a lock but very few will have walked along the bottom of one.”
The event is free and the last lock entry time is 3pm.