Is best to visit Danshui in the late afternoon before sunset, the best place to view the sunset is located at Danshui Boat wharf. You can visit the Danshui historical street, Hongmao Castle, Little White House, Red Castle, Long San Temple which is all around the vicinity.
Before you go Thamsui, take my advice, plan your schedule in the evening, I am sure you don't want to miss Tamshui sunset as it is the main attraction in Tamshui and some says in Taiwan too.
The weather might be very hot during summer, don't forget to put on sun block if you are not used to stay under the sun.
While waiting, you can also enjoy some local food alone the river bank.
Over the left bank of Tamshui River, the archeologist found the early civilization in Taiwan, the Shisanhang People.
The local government has built a very fantastic museum to show tourist how is archeology work in Taiwan and how is the early civilization started in Taiwan.
In Tan-shui there is a major university, although I forgot the name. There is a beautiful garden, which I found to exhibit some ambience.
I wouldn't suggest going out of your way to visit this, but if you are around Tan-shui, you should stop by - the campus is beautiful and the garden is perfect.
Fishermen's Wharf is newly constructed in these years. It is also built as a park.
Both the fisher's boats and the tourist's boats stop at the pier. There is the boat from the pier to the Tanshui old town which is not far from the MRT station. You can also take the tourist boats which go around the river or even go along the north coast.
There is also a fish market close to the pier. You can buy both the fresh fish or have the cooked fish at the restaurant.
The long wooden walkway and the lover's bridge is the most famous features at the pier. There used to be many people walking there.
Alethia University was found by the missionary Dr. George Leslie Mackay in 1882. It was called Oxford College at the time to memorize Mackay's hometown, Oxford County in Canada.
You can still see the old building of the Oxford College in the campus. It is a special architecture mixed with the traditional Chinese style and the Christian decorations such as the color glasses. They also built a new and grand church recently.