I’ve always found the best way to explore a city is by foot. You can’t really experience the same thing in a car or tour bus. Most of the major cities offer walking tours.  Usually the tours are priced well below a comparable bus tour and they provide an intimate perspective you aren’t going to get sitting in a vinyl seat.  London’s Original London Walks tops my list for variety of tours and expertise of the guides.  Many of the walking tour guides in London have a vast knowledge of British history and you never know what you’ll learn on one of these trips.  I took the walking Pub Tour in London and discovered the history of Viking attacks on the city of London that shaped much of the way the city was designed.
 
If you don’t find a walking tour that interests you, you can always go self-guided.  There are several sources of self-guided tour books.  One of them is City Walks: 50 Adventures on Foot - a collection of suggested short walking tours for a specific city.   Each collection comes in what looks like a large pack of cards. Each card has a walking map on one side and on the opposite, points of interest, suggested stops and other insider information.  It’s a fun way to explore small sections of a city.  Make a game of it. Close your eyes, pick a card and you’re off on a new adventure.  You can order City Walks on Amazon.com.  Here are the current cities covered:

• City Walks: New York: 50 Adventures on Foot 
• City Walks: San Francisco: 50 Adventures on Foot   
• City Walks: Amsterdam: 50 Adventures on Foot 
• City Walks: Boston: 50 Adventures on Foot
• City Walks: Washington, D.C.: 50 Adventures on Foot  
• City Walks: Paris: 50 Adventures on Foot 
• City Walks: London: 50 Adventures on Foot
• City Walks: Rome: 50 Adventures on Foot (City Walks Deck)

Coming soon

• City Walks Deck: Chicago: 50 Adventures On Foot 
• City Walks: Vancouver: 50 Adventures on Foot 
• City Walks Deck: Los Angeles