I’ve decided to start a new mini-series on how to group your visits to various London sites into manageable portions. I’ve had several rounds of American guests come to visit and find that I’m consistently recommending the same tourism strategies, so let’s get started with a bigun’ that knocks out the bulk of the must-see quintessential London sites.
My suggested Thames Circuit can be picked up at any point and followed clockwise or counter-clockwise with different options along the way…doesn’t really matter to me; it’s your choice! For sake of illustration, however, I will start at Westminster Tube Station.
As you emerge from the Tube, you will be greeted by the most familiar London site ever—Big Ben (well, it’s actually the massive bell that’s inside the clock tower that’s nicknamed Big Ben). Extending beside and behind Big Ben are the houses of Parliament, and if you want to take this opportunity to duck over and see Westminster Abbey as well, by all means go for it. It charges admission, but surely provides a compelling atmosphere and history (and Jeremy Irons is downright delightful to listen to as your audioguide).
Crossing Westminster Bridge will take you to the South Bank, where you can visit the Aquarium, Movieum, or the unmissable London Eye. Continuing Westward along the South Bank will give you a pleasant vantage of the cityscape and river. Eventually, you’ll find yourself approaching the Tate Modern art museum and Shakespeare’s Globe Theatre—if it’s the arts that take your fancy, wander through the Tate or take a tour to learn about the original Globe Theatre (or even catch an actual performance in the open-air there as Shakespeare would have intended).
You can continue on from here or perhaps dash across the Millenium Bridge to view St. Paul’s Cathedral up close if its striking image across the water has been tempting you up to this point—its dome continues to tower above the surrounding buildings. Otherwise, continuing on along the South Bank will ultimately bring into view the Tower Bridge (the one that many confuse with London Bridge), another renowned symbol of London. Crossing the bridge here will deliver you unto the gates of the Tower of London, in which you can view the Crown Jewels and medieval weaponry as well as follow a Beefeater tour of the grounds of this former site of 
imprisonment, torture, and execution, including where Ann Boleyn was beheaded. Just beyond the Tower is a small park atop Tower Hill itself, where the Tower’s prisoners were executed for all to see (and near which you can catch the Tube to your next destination of choice via the Tower Hill station). If you are in no particular rush at this point, you might want to pop into the Hung, Drawn, & Quartered pub if you’re feeling a bit peckish/thirsty or linger at the Tube station for the evening Jack the Ripper tour to explore more of East London and its sordid past.
