No stealing, no vandalising, no speeding: we all think we know the law. But the rules you think you know can change drastically once you go abroad. In some countries, the most innocuous acts, such as drinking water or stepping on money, could land you with a fine or even a lengthy jail sentence. Here are some of the most unusual laws around the world, from the practical to the utterly bizarre.

In super-clean Singapore, it’s not just chewing the gum, but also importing it that is a total no-no. The ban on chewing gum was introduced in 1992 as just one of many laws to improve the cleanliness of the island: there are also bans on spitting, graffiti and littering. However, as of 2004, chewing gum with health benefits, such as nicotine gum, are available for purchase.

Think twice before packing any trendy khaki gear: wearing camouflage print in Trinidad and Tobago could get you in trouble with the law. The pattern is banned in the country to prevent those who aren’t in the military from posing as soldiers.

Watch where you walk if you're in Thailand, because inadvertently stepping on Thai money could land you with a hefty jail sentence. Thai banknotes have the image of the King on them, and stepping on them could be construed as an insult to the monarchy.

Leave the stilettos at home if you’re planning to visit some of Greece’s famous ancient sites. Heels have been banned at many of the country’s awesome archaeological sites, such as Athens’ Odeon of Herodes Atticus, due to concerns that the footwear could damage monuments.

You might like to stay hydrated on the plane, but leave your bottles of water behind when you land in Nigeria: it’s illegal to bring mineral water or soft drinks into the country. Those who do could be subject to fines and confiscation.

Whether it’s light or dark outside, if you’re driving in Denmark, you must have your headlights on at all times. If you accidentally forget to turn them on, you could be landed with a substantial fine.

You might think that feeding the pigeons in St. Mark’s Square is a quintessential Venice activity, but beware: this tradition was banned in 2008 due to fears the historic buildings in the square might be damaged by increasing numbers of the pests. Tourists who flout the law could face hefty fines.

You might think all you have to do is look right and left before crossing the road, but in America, you’d better make sure you’re only walking on a specified crossing with a green light. If you do jaywalk, you could be slapped with an on-the-spot fine and could even be arrested.

Lots of us use nasal sprays for allergies or colds, but carefully check the label of your medicine before you travel to Japan: it’s illegal to take some common nasal sprays containing pseudoephedrine into the country, and those who unwittingly break the law could face a fine.

Beware if you’re organising a hire car while holidaying in Spain: it’s not only illegal to wear flip-flops while driving, but also to wear backless shoes, footwear that is open at the front and high heels when behind the wheel. And don't even think about driving barefoot. Those who contravene the law could be faced with fines if caught.

It’s not clear how anyone could actually be caught doing this, but if you enjoy using the sea as a toilet, avoid doing so in Portugal – not least for your fellow swimmers. This law was put in place to keep beaches family-friendly.

Whether you’re Muslim or not, if you are in the United Arab Emirates during the holy month of Ramadan, you’re expected to stick to the rules and refrain from eating or drinking in public. If you break the law, you could face a large fine or even jail time.

Speed camera location warnings are one of the best things about satnavs. However, making use of this feature is illegal in France and could land you with a fine of up to €1,500, as well as six points on your driving licence.

If you’ve usually got a potty mouth, you might want to keep it shut when in Australia. In New South Wales, police have the power to charge anyone who curses in public with a $500 on-the-spot fine.

It might be tempting to save on data roaming charges, but if you connect to someone else’s wi-fi network while in Singapore, you’ve officially broken the law. The government views this action as hacking, and if you break the law, you could face a fine of $10,000 or a three year jail sentence – or both.

In Germany it pays to be prepared: it’s illegal to stop while on German autobahns, even if you run out of petrol, so make sure you fill up before embarking on any epic road trips. You'll be fined if not.

Well, not all of Canada, or we’d never have Drake, Celine Dion or Justin Bieber, but in Petrolia, Ontario, there’s a rule to prevent yelling, shouting, whistling, hooting or singing at all times.

There’s nothing more frustrating than being told to smile if you’re not in the mood, but in Milan it’s actually a legal requirement. An old law requires people to smile in public places. The only people who can frown without risking a fine are those attending funerals and also hospital workers.

The famous coffee-shop culture in Amsterdam doesn't mean that using drugs is allowed in the Netherlands. Soft drugs are only tolerated in designated areas, and if you possess or buy prohibited substances, you could face a prison sentence.

Be sure to indulge in all the food and drink you'll need before you get behind the wheel in Cyprus, because you could face a high fine if you’re caught even taking a sip of water while driving.

It’s not really clear this can be enforced, but one village in southwest France banned people from dying as the cemetery was too full. The mayor of Sarpourenx issued a statement saying: “all persons not having a plot in the cemetery and wishing to be buried in Sarpourenx are forbidden from dying in the parish… Offenders will be severely punished.”

Most people would assume that the make-up of their beds would be their own business, but not in Argentina. The country banned feather beds, on the grounds that “such an indulgence induces and encourages lascivious feelings”.

Need the loo late at night? Better not go in Switzerland: it’s not only illegal to flush the toilet after 10pm if you’re in an apartment, but also illegal for men to urinate standing up late at night.

In yet another bizarre, toilet-related law, it’s illegal to pass wind in public in Florida after 6pm on Thursdays. Very specific, but you’ve been warned.

Feeling peckish? Wait till you get back to your hotel to eat or drink if you’re visiting Florence: it’s an offence to sit on steps and courtyards, or to eat and drink in the immediate vicinity of churches and public buildings throughout the city. If you break the law, you could be slapped with a large fine.

Just one more toilet-related example, we promise: while we’d hope that everyone flushes after using the toilet, in Singapore, it’s an actual law. If you leave without flushing, you could be fined nearly £100. There’s also a law against urinating in elevators: they’re equipped with Urine Detection Devices (UDD), which detect the misdemeanour, set off an alarm and shut the doors until the police arrive.

Make sure you keep your car looking spotless if you decide to drive in Russia, as driving a dirty vehicle, especially if it obscures your number plate, can land you with an on-the-spot fine.

Well, not all of Spain: specifically, Barcelona, where, a few years ago, a new law came into place banning people from wandering the streets of the city in swimming costumes. If you’re spotted wearing a bikini, swimsuit or trunks away from a swimming pool or beach, you could be landed with a fine of up to €300.