At first glance a large industrial town in Co Antrim and a small British overseas territory on the south coast of Spain have little in common.
Home to more than 27,000 people of mainly British and Spanish ancestry, Gibraltar or 'the Rock', as it is more commonly known has its own government and police force.
Although its sovereignty has been a major point of contention for over 300 years, it recently signed an agreement with Britain and Spain which confirms the right of Gibraltarians to self-determination.
Gibraltar also attracts ferry loads of tourists each year keen to experience its Mediterranean climate and tax-free status.
Ballymena, on the other hand, enjoys a lower profile internationally.
Often caricatured as the heart of the north's Bible Belt, the town's most famous son is perhaps veteran DUP leader Ian Paisley.
It has been struggling with the tag of sectarianism in recent years, from the high-profile loyalist protest outside the Catholic Church at Harryville, to the murder of Catholic teenager Michael McIlveen.
However, Ballymena Borough Council recently hosted an official ceremony to celebrate its twinning arrangement with Gibraltar, after more than three years in the making.
William Young, cultural services manager in the council, who has just returned from 'Gibraltar Day' celebrations in London, insists the town and Gibraltar have a long shared history.
"During the Second World War the entire resident population of Gibraltar was evacuated. Over 100 people came to Ballymena,'' he said.
"There were nine specially constructed camps just outside Broughshane and they lived there from 1943 to 1948.
"A number of Gibraltarians stayed on after the war and some of the local residents went with them back to Gibraltar.
"There was an affinity between the people and we wanted to capitalise on that."
Mr Young said the arrangement was set up to allow the council and the government of Gibraltar to forge closer links.
"It's an exchange between the people of Ballymena and the people of Gibraltar, not an exchange between Ballymena council and Gibraltar," he said.
"On an annual basis people from Ballymena will be going over to Gibraltar and vice-versa.
"There are plans to have musicians from Ballymena to play in Gibraltar and we are trying to get our two museums to talk with each other.
"There are artefacts in Ballymena that would be useful for the Gibraltar museum and there are things that some of the Gibraltarians took home that we would like to have too."
Most towns and cities in Ireland have set up twinning arrangements:
- Newry and Mourne district council is formally linked with both the Western Isles Council in Scotland and Clare County Council
- Strabane is twinned with Sioux Falls in the US state of South Dakota and the east German town of Zeulenroda-Triebes
- Belfast has a twinning agreement with two other cities Nashville, Tennessee, the home of American country music, and the industrial city of Hefei in central China
- In 1994 Belfast and Nashville agreed to promote cultural, tourism and business development opportunities between the two cities
- Belfast set up its twinning link with Hefei last year, aimed at helping businesses in the north to forge links with the Chinese market