When faced with the question of which is the shortest border in the world, a number of answers might immediately spring to mind.

You might choose the frontier between Russia and North Korea, which stretches for about 12 miles.

Or you might think of the border between the Vatican City and Italy in Rome.

Known of course as being home to the Pope and a trove of iconic art and architecture, the Vatican is actually a city state in its own right.

Its border with Italy's capital runs for just over two miles, which makes it one of the shortest in the world.

However, you would need to cast your eye further south to discover the world's smallest border.

In Sub-Saharan Africa are the countries of Namibia, Botswana, Zimbabwe and Zambia, all of which are fascinating places to visit.

It appears as if all these countries converge at one single point. However, if you look more closely, you will find the answer to the original question.

The 150-metre-long (492ft) boundary between Botswana and Zambia is the shortest land border in the world.

The Botswana–Zambia border connects two tripoints on the Zambezi River, one with Namibia in the northwest to one with Zimbabwe in the southeast. This land boundary is also known as the quadripoint area, which indicates the meeting of four distinct political territories.

The double tripoints were made while the nations were under colonial rule.

While all four of the other boundaries received official delimitations, the Botswana–Zambia frontier has never been formally agreed upon.

Botswana and Zambia have not revisited their boundary delimitation since independence, but the two states maintain good political relations.

Some would argue that the shortest border is actually between a Spanish enclave, Penon de Velez de la Gomera and Morocco, which covers just 85 metres (278ft).

Others would point out that if the cities of Ceuta and Melilla were counted, then the total length of the Spain - Morocco border would be much longer.