Since Mum has been here, we've really been trying to hit all the good bits.
The view of the North End from a super fantastic semi-secret free tourist spot. That white steeple you see is the "One if by land, two if by sea" tower at the Old North Church with the Bunker Hill Monument in the background:
The T station at Harvard Square:
On the water under the Longfellow Bridge:
On the water under the bridge near the Museum of Science:
The rest of the Boston photos are here in the flickr set.