Like anyone who's lived in London for a few years I have my own list of things you Must Do if you're visiting. You should do a walking tour, visit a museum and a park, take a boat trip down the Thames, check out the views from on high at the Shard or London Eye, enjoy afternoon tea, see a show in the West End, visit a market and walk the South Bank.
Also on that list is the number 1 tourist attraction in London. Many people will suggest that you avoid the tourist spots and focus on seeing the "real" London. But, tourist spots are tourist spots for a reason and the Tower of London is the epicenter of London and British history, it is real London.
