There are a handful of fantasies embedded in the brain of every Londoner. Among those not too depraved to mention is the idea of balancing on top of the city's newly inaugurated architectural wonder-phallus The Shard, looking down on all below you and laughing like a vertigo-baiting super-villain. 'London: A City Through Time' allows you to do just that. Download it onto your iPad (it costs a tenner, but bear with us), skip to the 'audio visual history' section, tap on '360 panoramic views' and scroll to the bottom of the list. Now, hold your device up in front of your face, move it around and gasp in wonderment as the best view in London moves with you. Even to our tech-saturated eyeballs, it's really rather impressive. Show it to anyone over the age of 60, then, and they'll probably think you're a wizard. That's not all the app does, of course. As well as loads of other interactive panoramas (we particularly enjoyed craning our necks to check out The Gherkin), there's a hefty library of old-timey photos and video -- including footage of the 1908 London Olympics -- GPS-aided audio tours, a comprehensive timeline of the city's history that goes right back to 501 BC and a 3D model of Westminster Abbey you can spin around with your pinky. In short, it's the best London history app we've ever seen, with the steep-seeming price tag actually proving fantastic value for money. David Clack London: A City Through Time is