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Dark burrows, winding tunnels through trees and shafts that seem to go to the centre of the earth – are you brave enough to enter these places of little light?
* Descend the spiral staircase to the old miners’ tunnel in Levant Mine, Cornwall. You can retrace the miner’s steps along the underground route and brave children can now stand inside the old shaft, looking at the drop below their feet.
* Go on a subterranean adventure in the old servant’s tunnel at Castle Coole, County Fermanagh.
* Climb down the spiral staircase into a secret, winding tunnel at the Old Battery on the Isle of Wight. This ex-military tunnel takes you to a hidden searchlight position, giving a dramatic bird’s eye view, directly onto the rocks below.
* Enter a world of little light and follow the twists and turns of the brew house tunnel at Calke Abbey, Derbyshire.
* Wind your way through the tunnel in the rhododendrons at Sheringham Park, Norfolk, to the viewing tower. This route is especially striking when the plants flower in late May and early June. Some of the rhododendrons are thought to be over 100 years old and little tunnels have been created to allow access to them.
* The Serpentine Tunnel, at Fountains Abbey in Yorkshire, was designed to give guests a gentle fright. It's still dark enough to be exciting today.
* Take the secret tunnel from our formal terraces to our wild Valley Garden at Cotehele, in Cornwall.
* Wander through the woodland paths at Allan Bank, in Cumbria, to discover the viewing tunnel.
* Discover the echoing tunnels of Uppark House, in Sussex, which would once have been used by the servants.
* There are hidden tunnels and pathways to explore at Biddulph Grange Garden, in Staffordshire.
More ideas for family days out
Uncover more top-secret places for curious children.