Sakura blossom, cherry trees in Tokyo, Japan

Sakura blossom, cherry trees in Tokyo, Japan, late evening.
People having dinner and parties in restaurant overlooking the river

Hanami "flower viewing"
is the Japanese traditional custom of enjoying the transient beauty of flowers; flowers in this case almost always refer to those of the cherry (sakura) or, less frequently, plum trees. From the end of March to early May, cherry trees bloom all over Japan.
In modern-day Japan, hanami mostly consists of having an outdoor party beneath the sakura during daytime or at night. The practice of hanami is many centuries old. The Japanese people continue the tradition of hanami, gathering in great numbers wherever the flowering trees are found. Thousands of people fill the parks to hold feasts under the flowering trees, and sometimes these parties go on until late at night. Usually, people go to the parks to keep the best places to celebrate hanami with friends, family, and company coworkers many hours or even days before. In cities like Tokyo, it is also common to have celebrations under the sakura at night. The cherry blossom front is forecast each year, previously by the Japan Meteorological Agency and now by private agencies, and is watched with attention by those who plan to celebrate hanami because the blossoms last for very little time, usually no more than two weeks. (From Wikipedia, the free encyclopedia)