After this week's chastening visit, Boris Johnson will probably think twice before returning to Luxembourg. But how much do you know about the little shard of Europe? Here are 14 nuggets of information.

1. It's one of the least happy countries on Earth, apparently

The annual Happy Planet Index ranks 140 destinations according to "what matters most - sustainable wellbeing for all". GDP takes a back seat; instead it's all about judging "how well nations are doing at achieving long, happy, sustainable lives". Costa Rica takes the top spot; bottom of the pile was Chad, followed by... Luxembourg, despite it being the country with the second highest per capita GDP in the world.

2. It has much in common with the UK

Because Luxembourg is a parliamentary democracy under a monarchy. Its official moniker is the “Groussherzogtum Lëtzebuerg” – ie the “Grand Duchy of Luxembourg”. The current head of state is Henri, Grand Duke of Luxembourg. He's 64, and has been on the throne for two decades – from 1998 as regent, and from 2000 in his own right.

3. It's bigger than popular opinion believes

There is a tendency to view Luxembourg as a microscopic fragment of the European landmass – when, in fact, at 998 square miles, it is roughly the size of the American state of Rhode Island. Admittedly, Rhode Island is the smallest of the 50 constituent parts of the USA, so that's an awkward comparison – but Luxembourg is nonetheless quite a lot larger than all those other European countries which are generally included in the Not Very Big Club. It's a lot larger than Andorra (180 square miles), Malta (122 square miles), Liechtenstein (62 square miles), San Marino (24 square miles), Monaco (0.78 square miles) and Vatican City (just 0.17 square miles). It also has a population of more than half a million (590,667 people). In others words, there is more to Luxembourg than you think.

4. And it is even more European than you assumed

And not just because it has three official languages (French, German, Luxembourgish) and three immediate neighbours (Belgium to the west, Germany to the east, France to the south). Luxembourg is home to Schengen, a village in its south-east – near the tri-point where France, Germany and the duchy meet – which gave its name to the open-borders agreement that makes for checkpoint-free travel across much of the European Union. It was signed in this pretty location – framed by vineyards, on the River Moselle – in 1985.

Luxembourg is quite a lot larger than all those other European countries which are generally included in the Not Very Big Club Credit: RubyRascal - Fotolia/Rachael Lomas

5. It has a very lovely capital...

This prettiness extends to Luxembourg City, which has retained some of the appearance and aura of what was once a formidable European stronghold. It was effectively founded in the 10th century by Count Siegfried I, Luxembourg's first ruler – who took a cluster of Roman ruins, and sparked their transformation into a swarthy armed citadel. Although some of the battlements were torn down as part of the 1867 treaty which defanged the duchy, enough of their magnificence lingers for the city to have earned Unesco status. In 1994, its “Old Quarter and Fortifications” were added to the Unesco World Heritage honour list, hailed as “a fine example of military architecture spanning several centuries”.

The city has earned Unesco status Credit: Boris Stroujko - Fotolia

6. ...in a beautiful location

Some of Luxembourg City's visual appeal can be pinned to its geography. Remarkably for a place which is often dismissed as a star pupil of flat, faceless European bureaucracy, the duchy's capital occupies a high bluff above not one but two rivers – the Pétrusse and the Alzette. Together, these waterways are responsible for a gorge, up to 230ft (70m) deep in sections, which has seen the city develop on several levels. Walking around the centre can be surprisingly tough on the legs, with staircases and slopes rearing up as challenges to the visitor. There are bridges too. The Pont Adolphe is arguably the most impressive, arching its broad back across the Pétrusse, with a drop of 138ft (42m) falling away below.

7. And it's easier to reach than you think

Fancy a weekend in Luxembourg City? You can reach it by train in just five hours and 28 minutes, with a change in Paris.

8. They eat a lot of meat

Exactly 107.9kg per person per year, on average, according to the Food and Agriculture Organization of the United Nations. Only the US, Kuwait, Australia and The Bahamas eat more.

Is that a Luxembourger? Credit: ALAMY

9. It punches above its weight when it comes to the Nobel Prize

Luxembourg has produced a pair of Nobel Prize winners (Jules A. Hoffmann and Gabriel Lippmann, of course). That puts it third on the list of prize winners per capita.

Most Nobel prize winners per capita

Faroe Islands - 1 per 48,199 residents St Lucia - 1 per 92,499 Luxembourg - 1 per 283,555 Sweden - 1 per 315,465 Switzerland - 1 per 319,179 Iceland - 1 per 329,425 Norway - 1 per 400,843 Austria - 1 per 406,885 Denmark - 1 per 436,083 UK - 1 per 497,813

10. It has a cathedral with a famous name

That name being “Notre Dame”. To be truthful, this doughty church cannot match the airs and graces of its Parisian “sibling”, but its mixture of baroque and gothic architectural stylings make it an intriguing landmark, elegant pillars rising to vaulted ceiling. It owes its split personality to the three centuries it took to complete it. The cornerstone was laid in 1613, but the last phase of construction was not finished until 1938 – just in time for the World War that is remembered in its cemetery. Here, you find one of three versions of Le Prisonnier Politique, a work in bronze by Lucien Wercollier – a Luxembourg-born sculptor who was imprisoned in the Hinzert concentration camp (just over the border in Germany) for refusing to kowtow to Nazi demands for “Aryan art”. A striking creation, it shows a slightly stooped, emaciated figure, with its hands apparently tied behind its back.

11. And a restaurant with very long wine list

Restaurant Chiggeri in Luxembourg City holds the Guinness World Record for longest wine list: 1,746 different labels at the last count.

12. There's lots of great contemporary art

Culture vultures can find a fair amount to detain them in Luxembourg City. MUDAM, the city's main modern art museum (Musée d'Art Moderne Grand-Duc Jean; mudam.lu) is a case in point – an innovative institution slotted into the carcass of the onetime Fort Thüngen (part of the old walls). It focuses on 20th and 21st century creativity, showcasing more than 100 artists, including Andy Warhol and the German photographer Thomas Struth – in a building which was designed by the feted Chinese-American architect I. M. Pei. Similarly alluring, the Galerie d'Art Contemporain “Am Tunnel” (see lcto.lu) trains an expert eye on important artistic figures of recent decades – including Luxembourg lensman Edward Steichen, a pioneer in fashion photography in the early 20th century. That it does so from within a tunnel in the defunct fortifications only adds to its aesthetic.

The Musée d'Art Moderne Grand-Duc Jean Credit: Kit Leong - Fotolia

13. Its main square is a compact delight

The Place d'Armes is the focal point of both the duchy and the city – a small square fringed by cafes, eateries and the gentle prospect of quiet summer afternoons where there is nothing more on the to-do list than a bottle of rosé. The bandstand in the middle hosts regular musical performances. And there are markets too – the “flea” variety held on the second and fourth Saturday of every month; the twinkly Christmas variety, in December.

14. It is a fine place to relax

Last year a spa-focused holiday operator published a "Relaxation Index", ranking 28 European cities according to factors such as population density and quality of public transport. Luxembourg City came second, behind only Copenhagen. Next year it might even take the top spot – the country plans to make all public transport entirely free from March 1, 2020.