What are the must sees in Boston when a person only has one day?

Why don't you try clicking on "destination" which is at the top of the page? Read it and then come back with more specific questions.

I was in Boston for 1 day about 2 weeks ago. I strongly recommend walking the Freedom Trail, taking a Duck Tour, and attended a Red Sox game (if they're playing). I did all three and it was a very memorable visit. If the Red Sox aren't playing, go to Cambridge or drive up to Marblehead, Mass.

In the morning, take the Duck tour, which will take you around Beacon Hill and part of downtown and past part of Cambridge, then go back in the afternoon and see whatever part you want to see more of.

Possibilities: Go up the Hancock or Prudential Center for the distant view; walk around the Public Garden (esp. see the pond and bridge and Swan Boats and "make way for ducklings" sculptures; then walk around Beacon Hill, esp. Louisburg Sq. to get a feeling for old Boston. Harvard Square and Harvard are a "scene," too. And Quincy Market/Harbor area are nice too (although somewhat disrupted by construction).

Boston is a fabulous city--filled with history, architecture and beautiful sights. One day is simply not enough to enjoy it all. I thought "sccors" response was excellent. She summed it up nicely. In addition, I would add that the Beantown Trolley is a nice way of seeing all the sights. You can hop off and on, as you wish. You will have to plan a longer trip, in the spring or fall at some other point. Hope you enjoy "my" city!!