The Basingstoke Canal runs from its junction with the Wey Navigation through its current terminus of Odiham.
The current end is just short of the Greywell Tunnel. The 1,120km tunnel collapsed in 1932 and is no longer navigable. It is now home a large bat roost and is a SSI. Due to this it is unlikely that the tunnel will ever be restored. There is a gate just inside the entrance to the tunnel preventing anyone from entering it.
Odiham Castle (also known as King John’s Castle) is one of only three castle built during the reign of King John. Its location was allegedly chosen as it was half-way between Winchester and Windsor. Legend has it that this was the location from which he rode to Runnymede to sign the Magna Carta. The site has been ruined since 1605.
Information about the Basingstoke Canal can be found on the Canal Authority website.