Can you remember the last time you stayed up all night? Party animals, night owls, insomniacs, jet lag sufferers, vampires and the most curious of travellers, unite! There is a 24-hour city with round-the-clock activities to enjoy at your sleepless leisure.
For clubbers in Berlin, nights out on the town only really kick off at around one or two in the morning while young Madrileños dine late and nonchalantly head out for alfresco botellones drinking sessions. In Reykjavik, the long summer nights - almost 22 hours of daylight - are as bright as the perpetual neon glow of the Las Vegas Strip.
If tiredness should start to take hold, just remember this: you can sleep when you're dead!
Berlin
Dusk-midnight: Darkness is falling and it's feeding time. Take an hour or two to refuel on light dumplings and the Intersoup with coconut milk at Soupanova (Stargarder str. 24) in Prenzlauer Berg. Serving through the night, live music or DJs perform from their flower-power style stage. Alternatively, try a late-night supper club. Fisk & Gröönsaken are among the cheapest hosts that invite people in to their homes for a meal (they can recommend where to continue the party afterwards too). Early hours: Come out to play at Salon Zur Wilden Renate (Alt Stralau 70). This fun club, located in an abandoned house, is something of a grown up's playground complete with ping pong table and crazy decorations. Dawn: If you can make it past the stern-faced bouncers, Berghain/Panorama Bar (Friedrichshain Am Wriezener Bahnhof) is the place to welcome in the dawn. The sun streams in with the opening and closing of the blinds in time with the minimal techno beats and gets a round of applause from dedicated clubbers. The party lasts all weekend and is still heaving at 8pm on Sundays. Rise and shine: For a souvenir of the night visit an Photoautomaten. These black and white photo booths are scattered across the city. On Sunday mornings, Mauerpark in Prenzlauer Berg hosts a massive flea market from 8am. Grab a cup of glühwein or tea and rummage through vintage fabrics, Weimar Republic souvenirs, and lps. Oh, there is a massive karaoke too!
Las Vegas
Dusk-midnight: After dinner, take a gondola ride through a Venice replica of St Mark's Square at the Palazzo hotel (open until 12am on Fridays and Saturdays). Begin your night with a quirky show of hypnotists, comedians or burlesque at Harrah's, the Variety or Harmon Theater. Alternatively, the Science Center performs the Rocky Horror Picture Show at 11:45pm. Sadly, all night marriages are no more in Las Vegas but you could try and squeeze in a service before midnight. Early hours: Thrill seekers can throw themselves off the 108th floor of the Stratosphere Tower as late as 1am in a controlled free fall with Sky Jump Las Vegas. For the best complimentary casino cocktails head to Wynn (3131 Las Vegas Boulevard South). Tip the waitress a dollar for your free mojito then try to find the secret Koi Pond room. Clubbers come pouring out at 3am and some do not make it past the casinos. Try the Venetian (3355 Las Vegas Boulevard South) where drunks stumble out of megaclub TAO and will be easy pickings for you in the poker rooms. Dawn: When sleepiness starts to take hold, catch the shuttle service from the Strip to Bootleg Canyon near Boulder City for a 50mph whizz down a zip line which opens at 7am. Rise and shine: On Sundays, take a refreshing dip at one of the Hard Rock Hotel Rehab pool parties complete with lifeguards and cabanas. It has been rated one of the top ten swimming pools in the world.
Madrid
Dusk-midnight: Dining around 10pm plus an end of meal coffee and sleep is the last thing on your mind. In fact, you can gorge on croquetas and pimientos del pardon until 2am in this city. Early hours: The most passionate of flamenco dancers usually appear in a tablao (a restaurant with a stage) after midnight. Try Casa Patas (Calle Cañizares 10) or join the young crowd at Cardamomo (Calle Echegaray 15). For a fabulous view of Madrid, the café at Circulo de Belles Artes (Calle Alacala 42) charges €2 to access its fabulous roof terrace and is open until 3am. Café Libertad 8 (Calle Libertad 8) is a cultural venue hosting all sorts from poetry readings to live music until 2:30am. It's close to the hip and pulsating bars of the Chueca district too. Rockers should head to the Wurlitzer Ballroom (Tres Cruces 12) armed with a few beers to keep you company in the queue. To party until dawn, Sala Stella (Calle Arlabán 7) is always a safe bet spinning funk and electro while Sala BarCo (Calle del Barco 34) attracts a fashionable but genuinely musical crowd. Dawn: Here, talk of 'afters' does not refer to dessert but to clubs that kick off at 7am and continue until the early afternoon. Macumba (Estación de Chamartín) is one such club opening 9am-8:30pm on Sundays and boasting Madrid's top soundsystem. Rise and shine: At the break of dawn there is the smell of warm milk, honey and sweet fried snacks wafting out of the breakfast joints. Try churros and chocolate at San Ginés (Pasadizo de San Gines 5) which is open 9am-6am and attracts a mixed bag of exhausted clubbers and sweet-toothed old ladies first thing in the morning.
Reykjavik
Dusk-midnight: Permanent twilight in winter and barely-there sunsets in summer, Reykjavik is perfect for muddling up your sleeping and waking hours. If you can't make it to the Blue Lagoon, a 40km bus ride from the city, the gorgeous Sundhöllin (Barónsstígur 16) is Reykjavik's oldest pool that uses geothermal water from the mountains.There are also two roof top pools open until 9:30pm midweek. Alternatively, Laugardalslaug is open until 10pm. Early hours-dawn: If you are ready to runtur (as it is incorrectly known to English-speaking tourists), the best bar hopping is along Laugavegur and Austurstraeti where most locals head for the weekend pub and bar crawl from 11pm. Popular spots include Ölstofan (Vegamotastigur 4) and taxidermy-clad Boston (Laugavegur 28) where locals invest in round after round in quick succession and stay out until about 6am. For live music, artists at NASA (Thorvaldsenstraeti 4) rarely take to the stage before 1am. In winter, it is common to see the northern lights dancing overhead as you hop from one drinking hole to the next. Rise and shine: For a slap-up breakfast to soak up last night's boozy indulgences, Grái Kötturinn (Hverfisgata 16a) offers American pancakes and freshly baked buttery bread in its somewhat lopsided art gallery/bookshop/café.
Thanks to mlaiacker, slideshow bob, elainne_dickinson, and christine zenino for the images off Flicker. Please note, all images were suitable for use at the time of publication according to the Creative Commons license.