Polish Prime Minister General Władysław Sikorski died in a plane crash near Gibraltar in 1943.
The Strait of Gibraltar is important for military purposes and the UK has a naval base there.
Spain has long sought to regain control of Gibraltar, which has been on the UN list of non-self-governing territories since 1946.
In a 2002 referendum, 99% of voters supported remaining under British rule.
In 2006, Spain and the UK signed a cooperation agreement that included building a new airport terminal and improving border controls.
The agreement also included compensation for Spanish workers who lost their jobs when the border was closed in 1969.
The first commercial flight from Spain to Gibraltar in decades took place in 2006.
The Instituto Cervantes plans to open a branch in Gibraltar.
In 2009, the Spanish Foreign Minister visited Gibraltar for the first time since British sovereignty began.
Tensions between Spain and the UK over Gibraltar continue to exist.

"Test your knowledge on the history and current affairs of Gibraltar with our quiz! From the tragic plane crash of Polish Prime Minister General Władysław Sikorski to the ongoing tensions between Spain and the UK, this quiz covers it all. Explore the importance of the Strait of Gibraltar for military purposes, the UN's classification of Gibraltar as a non-self-governing territory, and the 2002 referendum that saw 99% of voters supporting British rule. See how much you know about the