Everyone knows it's there. Everyone knows its name. But does everyone know these 10 facts about Ayrshire's famous lonely island?
Here are 10 facts you might not have known about Ailsa Craig.
1- Its exact height and size
The island stands at over 1,100 ft at its highest point and takes up around 240 acres of the sea.
To be precise, the island is measured at 1,109 feet, which is around 338 metres tall.
2- Nobody lives on the island
The island has been uninhabited since automation in 1990.
3- The current owner of the island
The island currently belongs to David Thomas Kennedy, the 9th Marquess of Ailsa.
He owns the entire island, apart from two hectares which were sold to the Northern Lighthouse Board in 1883.
4- The island is currently up for sale
In 2011, it was announced that the island would be put up for sale, with the asking price being around the £1,500,000 mark.
Despite this, it still currently belongs to The Marquess of Ailsa.
5- A hotel was planned to be built on the island
Planning was lodged to build a five-star hotel on the island. However, planning regulations prevented this from happening due to too much work needing to be done.
6- The island still has some fully built buildings
The only buildings on the island are the lighthouse on its east coast, facing the Scottish mainland, a ruined towerhouse and the old quarry manager's house that is used by the RSPB.
The lighthouse on the island was built between 1883 and 1886 by Thomas Stevenson, who was a pioneering Scottish civil engineer.
7- The island has a rich history of creating curling stones
Ailsa Craig has large and varied quantities of fine Granite that was mined for making curling stones from the early 1800s, until 1971.
Many of the top curling stones that are used today are made from this granite.
Kays of Scotland has been making curling stones since 1851 and has the exclusive rights to the Ailsa Craig granite, granted by the Marquess of Ailsa.
8- The island has had a number of uses during its time
The castle was built by the Hamilton Family to protect the island from King Philip II of Spain.
Ailsa Craig was also a haven for Roman Catholics during the Scottish Reformation.
Due to its secluded nature, the island was used as a prison during the 18th and 19th centuries.
9- Two railway tracks used to run through the island
The island also had two railway systems which would transport supplies to the lighthouse and transport road stone from the quarries.
A trip to the island would show that one of these railway lines is still largely intact.
10- The island has a number of nicknames
Ailsa Craig is sometimes referred to as "Paddy's Milestone", as it is approximately the halfway point of the sea journey from Belfast to Glasgow.
As a result of being the most conspicuous landmark in the channel between Ireland and Scotland, the island is also known by a number of different names such as The Rock, Alisdair's rock, Elizabeth of the ocean and Alasan.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here