You can’t see the Great Wall of China from the moon

It’s just too far away. You may be able to see it from space, because space isn’t that far. If you went straight up from Nelson’s Column in Trafalgar Square, you’d reach space more quickly than you’d reach Scotland. It’s only about 250 miles up.

Vikings used ravens to help them find and conquer new lands

Ravens can’t land on water, so the Vikings would take them out in their boats and release them above the sea to watch where they flew. If the ravens couldn’t see land, they would come back to the boat and you’d travel a bit further and let them go again. When they didn’t come back, the Vikings would follow the birds to the nearest bit of land. This is how the Vikings were able to get all the way to North America. There’s plenty of evidence that they were in Newfoundland long before America was ‘discovered’ by Columbus in 1492.

The capital of Thailand is not Bangkok

Only westerners tend to call it Bangkok. It’s actually called Krung Thep – or, in full, Krung Thep Mahanakhon Amon Rattanakosin Mahinthara Ayuthaya Mahadilok Phop Noppharat Ratchathani Burirom Udomratchaniwet Mahasathan Amon Piman Awatan Sathit Sakkathattiya Witsanukam Prasit. The abbreviated version is pronounced ‘grung tape’ and means ‘city of angels’, the same as Los Angeles.

Victorians dug the Channel Tunnel in 1880

Enterprising Victorians created a boring machine (a type of drill, rather than an uninteresting tool) in 1880, and some Welsh miners were able to bore right down at the Kent coast. Despite having this technology, plans to create a tunnel from England to France were abandoned, due to deteriorating relations with the French.

Land of the Free is not the national anthem of the USA

It’s the national anthem of Belize, the tiny Central American country. The US national anthem is The Star-Spangled Banner, though ‘land of the free’ is in the last line, so you’d be forgiven for confusing them. Star-Spangled Banner was jotted down on the back of a letter during the War of 1812, and was originally set to the tune of an English drinking song. Bonus fact: Belize is the only country to have people on its national flag.

Nigeria has the second-largest film industry in the world

Nigeria makes about 2,500 films a year, which equates to around 50 a week (Bollywood in India is the world’s largest film industry, while Hollywood is third). Film is Nigeria’s second-biggest employer, after agriculture, and worth five per cent of the country’s GDP. Almost all the films are sold on tape or DVD in markets – barely anyone sees them in the cinema.

Alan’s new DVD, Little Victories, is released on 28 November 2016.

Interview by Etan Smallman