Literally all over the city. Many local people do not shower in their own apartments but use these public shower houses instead. There are upscale, midrange, and low end places. Check with a 5-star hotel to get the most up to date facility for the type you prefer. Upscale spas will cost about ¥120 plus additional ¥200 and up for a massage. Low end ones cost ¥30 plus an additional ¥100 for massages. Shanghai Tan (上海摊 Shànghǎitān) and Jiannianhua (嘉年华 Jiāniánhuá) are two of Harbin's longest established sauna/bath houses, but nowadays their facilities are entirely neglected as new entrants divert customers.
中央大街 Zhōngyāng Dàjiē; lit. Central Avenue
This cobblestone lined street is a pedestrian only street that could serve as a perfect remnant of the bustling international business activities at the turn of the 20th century. The 1.4-km long street is a veritable museum of European architectural styles, including Baroque and Byzantine façades, Jewish architectural wonders, a Russian restaurant, French fashion houses (Fake Chinese Brands), American snack food outlets (Mcdonalds and KFC and a Chinese owned "American Bar"), and a Japanese restaurant. In winter, one can walk out onto the ice or take a dog sledge or horse sledge ride. It is the prettiest site in Harbin as far as the city itself is concerned, however, if you go mid-day during the weekend be prepared to push through the crowds.
冰雪大世界
A magical kingdom built with 400,000 cubic meters of ice and snow. Highlights include the 500-meter super ice slide, the Snowflake Ferris Wheel, and the Asian同心 Main Tower. Lights turn on around 16:00-16:30, creating a dreamlike atmosphere.
松花江铁路桥
Built in 1900, this was the first bridge across the Songhua River in Harbin and served the railway system for over 100 years. In 2016, with the opening of a new bridge nearby, it was converted into a pedestrian bridge. It offers excellent views of the river and the city skyline.
圣索非亚教堂 Shèngsuǒfēiyà Jiàotáng
One of the few still standing Orthodox churches in the city. It is now converted into a Harbin Museum of Architecture. Inside there are exhibitions of many photographs from old times. Definitely worth going into, however, if you are used to European Churches do not expect the quality.
哈尔滨犹太新会堂 Hā'ěrbīn Yóutài Xīnhuìtáng
Has been restored and contains an impressive collection detailing the history of Jews in Harbin. There were 20,000 at one point and the synagogue is well worth a visit. Further up Tong Jiang Jie is the old synagogue that is now a youth hostel and cafe, with the old Jewish school next door -both worth a detour to look at from the outside.
极乐寺 Jílèsì
Large and active Buddhist temple.