Spinnaker Tower in Portsmouth

You're standing at the Spinnaker Tower in Portsmouth, right on the harbour at Gunwharf Quays. Take a look up. Two huge white steel arcs sweep towards each other, tied together by crossbeams. Together they form a spinnaker, the kind of sail that balloons out in the wind. It's the city's nod to its long bond with the sea. The tower is 170 metres tall, one of the tallest structures you can visit in Britain outside London. You can even spot it from the Isle of Wight.