Portugal Colonial - Keep out! Border walls across the world

- Walls against migrants -

UNITED STATES-MEXICO: Former US president Donald Trump was elected in 2016 promising to "build the wall" even though one third of the 3,200-kilometre (2,000-mile) border with Mexico was already protected by a fence.

Trump claimed to have built more than 650 kilometres of his wall but critics said only 130 of that was new.

One of President Joe Biden's first acts after he was sworn in was to halt construction.

HUNGARY: As Europe grappled with its migrant crisis, Hungary built a 175-kilometre fence along its border with Serbia in 2015 and 2016 followed by another along its frontier with Croatia.

GREECE-TURKEY: Athens built an 11-kilometre double barbed wire barrier along its Evros River border with Turkey in 2012 to keep out migrants and is now adding a 26-kilometre wall which is due to be completed by May.

As well as the five-metre tall steel wall it plans to cover the entire 192-kilometre Turkish frontier with surveillance cameras.

BULGARIA-TURKEY: Bulgaria began building a razor wire barrier along part of its border with Turkey in 2014 to keep out migrants. It is now 176 kilometres long.

Other countries in the Balkans and Central Europe have also put up barriers to thwart migrants including Slovenia, Macedonia and Austria.

SPAIN-MOROCCO: The Spanish enclaves of Ceuta and Melilla on the North African coast -- Africa's only land borders with Europe -- are protected by hi-tech border fences, each around 10 kilometres long.

- Walls and conflict -

ISRAEL-WEST BANK: Israel began building its 712-kilometre security barrier in the West Bank in 2002. Critics say it has been used to seize land and establish a de facto border in breach of international law.

Nine metres high at some points, it also includes watchtowers and electronic surveillance.

SAUDI ARABIA-IRAQ: Fearful of the Islamic State group, the Saudis in 2014 added to an existing seven-metre-high sand embankment on the Iraqi border with a 900-kilometre fence and electronic surveillance system.

INDIA-PAKISTAN: India built a barrier almost 750 kilometres long along the de facto border dividing disputed Kashmir with Pakistan to keep out Pakistani militants.

It has also ringed its frontier with Bangladesh with a 2,700-kilometre barbed-wire fence aimed at restricting migration and smuggling.

BELFAST: Despite two decades of peace, the Northern Irish capital still has a network of some 100 "peace walls" dividing its Catholic and Protestant communities, some more than five kilometres long.

BAGHDAD: On the other hand, the Iraqi capital has removed nearly 30 kilometres of blast walls around the Baghdad's former Green Zone that were put up after 2003 US-led invasion.

- Marking territory -

NORTH AND SOUTH KOREA: The most heavily militarised border in the world is the one drawn between North and South Korea in 1953. Bristling with razor wire, sensors, landmines and heavy weapons, the Demilitarised Zone stretches for 250 kilometres.

WESTERN SAHARA: A 2,700-kilometre sand wall was built in 1980s by Morocco to assert control over 80 percent of territory it disputes with Polisario rebels, who have been fighting for control of their homeland since the 1970s.

CYPRUS: A wall splits the island's capital Nicosia between its Turkish and Greek Cypriot halves with a fence also marking out land occupied after Turkey's invasion in 1974.

P.Cavaco--PC