One of Denmark's major tourist attractions, the Rubjerg Knude Fyr lighthouse, is relocating because of coastal erosion and shifting sands.
The lighthouse is only a few metres from the edge of a slope above the water.
The move has been planned for 18 months, and for the past ten weeks, engineers have been preparing for the operation to move the 1,000-tonne tower in one piece.
It is being shifted on a rail system that has been compared to roller blades.
Hjørring Municipality estimates up to 25,000 tourists will visit for the occasion.
The lighthouse is being moved 70m at a top speed of 8m/hr.