The Greenock Titan Crane was built in 1917 by Sir William Arrol & Co Ltd - one of the leading Glasgow engineering firms of the 19th and 20th Centuries.
The company built some of the UK's most famous steel structures, including the second Tay Bridge, the Forth Bridge and Tower Bridge in London.
The giant cantilever crane at Greenock stands 150ft (48m) tall and was once rated to lift 150 tonnes - the equivalent of about 30 adult elephants.
In Inverclyde's shipbuilding heyday it was used for lifting the heaviest objects into ships, particularly engines which were often made by the nearby Kincaid works.