We have a very short stay in London. I was hoping to try to see the Tower of London, The Tower Bridge (no tour, just see it), and the Royal Observatory in one day. Is that possible? Thank you for your input.
The Tower of London and Tower Bridge can be seen in one day because they're adjacent. A lot of people cross the Tower Bridge on their way to the Tower of London. However, I cannot answer your question about the Royal Observatory.
Yes, take the Thames Clipper riverboat to Greenwich from Tower Pier or the DLR (Docklands Light Railway) from Tower Gateway Station.
In December we took the tube, then the DLR to Greenwich. From there it’s a 20-30 minutes walk up to the observatory; about half of which is uphill. I felt the price for the observatory was excessive considering what’s there, but if you want to stand on the Prime Meridian you need to pay.
If taking the DLR remember to tap in and out. For something different, after the observatory we took the Greenwich Foot tunnel under the river, then picked up the DLR.