They have guided sailors and captains into Aberdeen Harbour for more than 150 years and have proved to be a staple on the waterfront.
Now, a pair of leading lights on Sinclair Road have been recognised as historically significant by Historic Environment Scotland (HES).
The matching set of cast-iron lighthouse-style lights are designated as B-Listed, meaning they are now registered as a site of historical and architectural interest.
They first became operational in 1842 and are pivotal in guiding boats and ships into the harbour during the darkest of nights.
The leading lights were designed by James Abernethy and have been described as the most sophiscated pair of their type in Scotland.
As a staple of Aberdeen Harbour, they have long been associated with the port.
Alex McIntosh, acting harbour master of Aberdeen Harbour Board, was pleased to see such an important part of the city recognised nationally.
He said: “Since 1842, these lights have been crucial for safe navigation in the approach channel into Aberdeen Harbour.
“They are monuments to traditional navigation methods that have stood the test of time, despite so many modernisations to vessel technologies and the port’s infrastructure.
“It is a privilege for them to be recognised as historically significant while still being used on a daily basis.”
The lights were awarded this designation after Aberdeen City Heritage asked HES to explore the possibility of them qualifying as a listed building.
After a thorough analysis, their importance to the region was recognised.
A spokesman for Historic Environment Scotland (HES) said “Aberdeen City Heritage Trust asked us to look at the pair of leading lights at Aberdeen Harbour to see if they qualified to be listed buildings.
“Leading lights were vital in helping vessels safely navigate their way in to the harbour. This pair were first used in 1842 and, although they have been heightened and have moved location within the harbour area, we found that they were of special architectural and historic interest and have listed them at category B.
“Their design as miniature lighthouses is unusual as is the early use of cast iron – they are the earliest surviving pair of their type in Scotland.
“Whale oil was originally used to fuel the lamps and they were converted to gas around 1877 – now they are powered by electricity and they have remained largely in use since they were built.”