The Ho Chi Minh mausoleum and museum are ponderous and overdone, but the park complex around them is gorgeous enough to make the visit worth it. Take a lengthy stroll thru the gardens and some of the older imperial buildings.
Not far from the tourist center near Hang Be, one can find the Water Puppet theatre on the northeastern shores of Hoan Kiem Lake. If you can imagine puppets being manipulated from BELOW, using a system of levers and strings in a tube which is submerged below the water, you have an idea of what the water puppets are like. I found them to be really cute. Some were solid, almost ceramic dolls that didn't have many moving parts. But others were soft fabric, such as the dragons, who went about the watery stage spewing fire and smoke amidst the clamor of cymbals and drums from the nearby orchestra. I enjoyed the show but the level of professionalism can be much improved. I visited the theatre twice. The first time there was incessant clatter from hammers and saws in a small construction area behind the stage. The second time one of the puppet rods snapped behind the curtain and the display was greatly compromised. In both cases there was not enough control of spectators standing up with cameras, causing distracting flashes or even worse, prolonged filming with Videocams. But the bottom line: I went twice because I loved the show. Definitely see a water puppet show if a visiting troupe passes by your area.
On the shores of Hoan Kiem Lake is a a small temple, Ngoc Son Temple. A small causeway in the lake leads to the temple on a petite island. One can find a several small altars, an art gallery and colorful painted dragons.
For a great selection of Hanoi City photographs, one of which I shamelessly snarfed up above since my photo was not as good, visit the website of Farofflands dot com. These folks went on a long world tour too...but not by bike. (BOO!)