As guests arrive on one of the longest days of the year, they will be dazzled by London under cloudless skies (we hope). The minimalist modern interior of Altitude 360 is the perfect backdrop on which to reveal the 2013 Hot 100 list. Altitude 360, at the top of Millbank Tower, can be reached directly from the River Thames. Simply catch the London River Bus. Hot 100 guests can watch the sun settle over the peerless London at night.