Josh Martin is a London-based journalist who writes across business and travel topics.

Who doesn’t like a 2-for-1 deal? A try one, get one free even? Through quirks of geography, fast transport connections or changing country borders, some major cities are parked right next to other equally worthy cities, yet many holiday planners under-appreciate this when plotting out their itineraries.

Twin cities are not to be confused with sister cities: that pointless tourism and business diplomacy exercise that has Wellington partnered with Harrogate and Hanoi, and Hamilton, the sister city of Saitama, Japan (no, I’d not heard of it either).

Not to be outdone by international options, a twin city break is available domestically too, of course. Napier and Hastings – forever combined in weather forecasts as basically the same place. They’re not though, and the small cities can easily be combined into one long weekend break – although one is definitely more appealing to tourists than the other, but I’ll let that debate rage in the comments below.

Bologna – Florence

If you can drag yourself away from Michaelangelo’s David, the steak fiorentina, the Uffizi Gallery, or one of the many glasses of Chianti on offer in Florence, there’s an even better foodie city just 40 mins away by rail. Trains, of which there are many dozens per day, start at around $17 each way, and drop you right in the city centre.

Bologna is all-too-often overlooked on a trip to Italy, but you’ll almost certainly eat better here than Milan, Venice or Rome, which is why locals call it “La Grassa” (meaning “the fat one”, since visitors can’t help but be gluttonous). Ragu tagliatelle (bastardised into spaghetti bolognese), mortadella, tortellini in broth are from the city, while Parma ham, balsamic from Modena and Parmesan cheese are all from the region.

New York City – Philadelphia

You’re in New York (concrete jungle, where dreams are made of), why leave for a second city? Precisely because the Big Apple is so, err, big. Far too much to bite off in one go, so maybe venture to something more digestible. On day two or three of your holiday? No. But looking for something different on day six? Try Philadelphia.

History buffs will already know Philly as the birthplace of the USA, where its declaration of independence and constitution were signed (the rest of us can learn it on a walking tour, or in the city’s many museums and attractions dedicated to the founding of America. All washed down with a Philly cheesesteak sandwich of course. Trains depart New York City’s Penn station for the 80-minute journey and tickets start at around $16 one way.

Dubai – Abu Dhabi

I’m sure the rival emirates don’t want to be seen as anything other than distinct, tourist-worthy metropolises, but they actually compliment each other rather nicely. Dubai, a frequent stopover city for kiwis flying to Europe, the Middle East and Africa, is famed for its gravity-defying towers, man-made island resorts and shopping but only about an 80-minute ride from Abu Dhabi.

This (slightly) less Westernised hub has its own Louvre art museum and the massive and multi-domed Sheikh Zayed Grand Mosque, which offer a nice cultural deviation from the bustling Dubai. You can catch a direct bus from Dubai’s Al Ghubaiba bus station to Abu Dhabi, but transfers and taxis are plentiful and much easier to sort.

Hong Kong – Macau

These twin SARs (Special Administrative Regions) of China in the South China Sea are well connected by frequent, high-speed ferries. Don’t trust your sea legs? The 55km Hong Kong-Zhuhai-Macau bridge is the world’s longest tunnel and sea bridge and cross-border buses can take you between regions in 40 minutes, plus time clearing immigration and customs (don’t forget your passport for this day trip!)

It’s the same for the ferry; you can devour dim sum in Kowloon for a late lunch and make it to Macau’s Vegas-level casino floors well before happy hour (it’s the only legal place to gamble in China). If blackjack’s not for you, compare and contrast the old world legacy architecture of old Macau’s Portuguese old colonial town, a Unesco World Heritage Site, with that of Hong Kong’s.

Biarritz – San Sebastian

France’s surf city and Spain’s gastronomic capital are heavyweight holiday spots in their own right, but being both in Basque Country, they’re only just over two hours apart by train. Easily falling into day trip territory, with an easy change at the border town of Hendaye/Hendaia between Spain and France – but given it’s all in the European Territory, don’t expect any formalities. There’s a cheaper direct bus connecting the cities.

The Basque influence, and that of the crashing Atlantic surf, gives Biarritz a completely different vibe to other French cities (although it still has Napoleon lll’s summer residence too). Meanwhile, San Sebastian is home of the pintxos (tapas/finger food), a top-tier tooth-picked morsel too delicious to simply call a bar snack. All washed down with local cider or Txakoli white wine, expertly poured into your glass from a height. Stuff your face, then paddle it off. Twinning is winning.