Lighthouse about to fall into the sea gets new life as a kaleidoscope

A century-old decommissioned lighthouse is getting another life as an art installation before the ground it stands on falls into the sea.

The Rubjerg Knude Fyr lighthouse in Denmark was built in 1900 and guided ships safely away from the coast of the North Sea for the better part of a century until it became evident that the structure was doomed due to erosion.

"The coast has been eroding about two meters per year. They've been fighting against the sand dunes since day one," architect Jan Tanaka tells As It Happens guest host Helen Mann.

Originally built 200 metres from the coast, erosion means the lighthouse only has another two to 15 years before it falls into the sea. The lighthouse was shuttered in the early '80s because the shifting dunes meant ships could no longer hear its foghorn.

Authorities turned the structure into a sand-drift museum until the erosion forced it to close 2002. The sands swallowed the outlying buildings up and the structure was abandoned until authorities decided to give it one last job.

Stairs were added to the lighthouse and, where the lantern once illuminated the coast line, a prism was installed.

"The light doesn't shine out, the light shines into the tower," says Tanaka.

The wind-powered prism casts natural light downward to a mirror-lined shaft of the structure. The effect is a giant kaleidoscope.

"For us, it almost feels like you're going back to school again because you'll never get a project like this again. It's kind of a man versus nature situation."

The project will stand until erosion encroaches on the "safe zone." The installation will then close and the lighthouse will be demolished.