A light installation called Standing Still has been put up in Sherwood Forest in Nottinghamshire by artist Simon Corder.
Many of ancient trees along the artist's route will be lit as living sculptures.
The centrepiece of the installation will be the Major Oak, which is thought by some to have been used as a hideaway by Robin Hood.
Night sights
The installation has taken five-kilometres of cables and 150 sets of lights using 100,000 watts of electricity.
Mr Corder said: "It is fairly dark and mysterious. There are lots of strange shapes and wonderful textures and colours on the old oak trees.
"We are also lighting up some sections of birch forest in a different style with some colour to give some contrast."
It is the first time the forest has been open to the public at night.
Conservationists say the low level of lighting should not affect the wildlife.
Simone Lennox-Gordon, from Nottinghamshire County Council, said: "The forest takes on such another lifetime in the winter that we wanted people to come and see it in that light.
"So this is why we have got this event going on because we wanted to extend the life of the country park for visitors."