This is a guest post by AARP International's Bradley Schurman, who was recently "stuck" in London for 12 hours. What did you do in London your first time? Tell us in the comments!
First things first: London is an expensive city. However, it can be done on budget. The exchange rate is hovering around $1.63 per pound, so I suggest keeping a calculator in your pocket to make sure that you know exactly what everything costs. You'll also want to check with your banks to let them know that you are traveling and to inquire about hidden charges while using your cards overseas - they can be surprising.
Grab a quick breakfast at a local establishment or a chain like Pret-A-Manger. If you want to be a bit more extravagant, head over to the food halls at Harrods. They are significantly cheaper than and typically as enjoyable as the hotel breakfasts, which can run upwards of $50 for a buffet.
From there, walk over to Buckingham Palace for the Changing of the Guard Ceremony. The pageantry starts around 11:00 and goes until 12:00. The ceremonies occur daily in the summer and less frequently in the fall and winter months.
After the ceremony ends, head down Birdcage Walk past the St. James Park to Westminster Palace. You'll know you've arrived when you see Big Ben. Americans can tour the Houses of Parliament, but only on Saturdays during the summer. Westminster Abbey, where the Duke and Duchess of Cambridge were married this summer, is just around the corner and costs about $25 per person to enter. (Tip: It's $5 off if you are over 60 and present valid I.D.)
From there, head over to Covent Garden for Lunch. There are pubs literally on every corner and each will provide you with an authentic British lunch - I suggest the fish and chips or Sheppard's Pie washed down with a Pimm's Cup or a pint of bitter. There are great street performers here and good shopping too.
From Covent Garden, follow the signs to Leicester Square. Look for the TKTS booth, which is the official seller of significantly discounted seats for London theaters. Shows typically start around 7:00, so if you miss the tickets at the booth, you can head straight to the theater for even deeper discounts. I saw Priscilla, Queen of the Desert in the orchestra section for under $100!
If you want to squeeze some shopping in during your stay, you should head over to Regent Street and Old (and New) Bond Street. Americans are exempt from the oppressive 20% VAT tax on all purchases over £50. Ask for "tax free" on these purchases and the sales clerk can usually help you get your money back.
Finally, if you want a quick bite for dinner that is a bit exotic, find a Chinese or Indian restaurant. Both of these cuisines are well rooted in British culture and curry is considered the national dish! My favorite Indian restaurant is Red Fort. However, it is on the chic and pricey side.
Photo: London silhouetted at sunrise. On the left: St. Paul's Dome. Photo by Flickr user curium.