This 558-foot-tall sail-shaped landmark with a $56 million price tag and an unfortunate history of "lift incidents" has bragging rights as being more vertically blessed than Britain's other top vertigo-inducing attractions: the London Eye, Blackpool Tower and Big Ben.
That said, visitors who might become a wee bit panicky when confined to dizzying observation areas needn't worry as Spinnaker Tower offers plenty of room to spread out across a trio of viewing decks. With an altitude of 328-feet, the first level is a good spot to ease into things (although the glass-floored Sky Walk isn't for those with weak knees and delicate constitutions). The second level's Café in the Clouds is the best place in the U.K. to enjoy really high tea while the open-air Sky Deck, hovering above Portsmouth Harbor at 360 feet, is all about the panoramic views.
Spinnaker Tower is also a popular spot for abseiling and exchanging vows, two activities probably best experienced without a belly full of the egg and watercress sandwiches served on the second level. Same goes for the upcoming Tower-Thon, an inaugural timed race up the concrete structure's 530 stairs that's due to take place in October 2015.