The Falkirk Wheel is to mark its tenth birthday

The Falkirk Wheel has celebrated its 10th birthday.

The boat lift was opened by the Queen in 2002 and is the only one of its kind in the world.

It links the Forth and Clyde Canal with the Union Canal, which sits 36ft (11m) higher, using a pair of water filled gondolas capable of carrying 600 tonnes.

HRH The Princess Royal was due to start the celebrations by unveiling artwork designed by local schoolchildren.

The anniversary will also be marked with the gathering of a flotilla of 60 vessels, which will include the oldest passenger boat in Scotland, the Ratho Princess.

The idea of a circular boat lift first appeared in Europe in the 1800s, but the method was first seriously considered by British Waterways for Falkirk in 1994.

Scottish architecture firm RMJM were selected to lead the team which came up with the final design, which cost £17.5m to build.

The wheel uses two rotating gondolas which can hold a combined weight of 600 tonnes.

The lift works as both gondolas remain in perfect as balance - any barge using them automatically displaces water equal to their own weight.

As a result, it takes very little power to rotate the lift, just 1.5 kilowatt hours of energy to turn, the same amount as it would take to boil eight household kettles.

The unique shape of the boat lift sought inspiration from a range of sources, both manmade and natural, such as a Celtic double headed spear, a vast turning propeller of a Clydebank built ship, the rib cage of a whale or the spine of a fish.

It remains one of Scotland's top tourist attraction with over 400,000 visitors a year.