London is a world unto itself. The eclectic neighborhoods, which are home to a blend of historical landmarks and modern-day attractions, can keep you occupied for days. If it is your first time in London, plan to visit the Tower of London, Tate Modern, Buckingham Palace or the British Museum before sitting down to a classic afternoon tea. The best time to travel to London is during the warmer months, but be warned that this is also the busiest and most expensive time of year.