The world's best urban playgrounds

1. Sydney

Not only does Sydney have that instant ‘wow’ factor, courtesy of its stunning harbour, but it also boasts a bewildering range of attractions, from bridge climbs to walk-through aquariums. Bright, clean, sunny and fun, Sydney doesn’t simply have suburbs, it has suburbs with surfing beaches.

Start with a cruise that drops you off at Darling Harbour, where a combo ticket provides entry to both Sydney Aquarium and Sydney Wildlife World, a breathtaking biome inhabited by wallabies, parrots, frilled lizards and other species.

If, however, you prefer warships to wombats, head for the Australian National Maritime Museum, a nautical feast that includes a replica of Captain Cook’s Endeavour. Hands-on science fun at the Powerhouse Museum is another option.

If your kids are aged ten or over, test their steel (and yours) on a Sydney Harbour Bridge Climb, where a clamber on ‘the coat hanger’ will get you 134m above the harbour for the ultimate photo opportunity.

2. Washington DC

Spies to space shuttles

Visiting the world’s largest museum complex might seem like slow torture for kids. But far from being dull, DC’s Smithsonian Institution Museums are utterly riveting. The National Air and Space Museum is a head-spinning shrine to flying. Exhibits range from the original 1903 Wright Flyer to the command module of Apollo 11. You can also handle a lump of moon rock, take a virtual journey through space and race paper darts.

At the Udvar-Hazy Center near the airport, a vast hangar gives pride of place to the space shuttle Enterprise, while more winged wonders can be seen in the butterfly garden outside the National Museum of Natural History.

Inside you’ll find an imposing African elephant in the Rotunda, a 15m-long right whale suspended in the Ocean Hall (new from 2008) and various dioramas in the Hall of Mammals. Not for the squeamish, the museum’s Insect Zoo holds tarantula-feeding demos and a chance to handle live insects.

If you prefer bugs of the electronic variety, slink over to the International Spy Museum where the KidSpy programme of workshops, demonstrations and action-packed missionswill hone the skills of every 0031/2 secret agent.

3. Vancouver

Green & serene

It’s hard to imagine a more family-friendly city park than Vancouver’s Stanley Park – a 4 sq km peninsula with walking trails, cycle tracks, a miniature train, horse-drawn carriage rides, a children’s farm, totem poles, water park and fantastic views of big ships coming and going. But it’s the Vancouver Aquarium that’s the park’s real crowd-puller.

In addition to habitat-themed displays from the walk-through Amazon gallery with piranhas, crocs and sloths to rocky coves inhabited by sea lions, sea otters and beluga whales, you can learn about marine mammal rescue and other conservation programmes.

Two of the best museums for children in Vancouver are Science World and the Vancouver Museum. Located about ten minutes from downtown Vancouver, Kitsilano Beach is a favourite with locals, while Grouse Mountain (accessible by cable car) has great views and hiking potential.

William Gray is the author of Travel with Kids, the first definitive worldwide guide to family travel.