Where is there a festival featuring people throwing tomatoes?

The answer is Spain

Explanation: La Tomatina is a festival that is held every last Wednesday of August in the Valencian town of Buñol, in the East of Spain. This festival has been holding since 1946.

During this festival, participants throw tomatoes and get involved in a tomato fight purely for entertainment purposes.

Explanation:

It’s been called the world’s biggest food fight. Every year on the last Wednesday in August, residents of Buñol joined by thousands of tourists hurl tomatoes at each other in a festival called La Tomatina. The festival got started in 1945 when a man began throwing tomatoes at a group of mischievous teenagers who had interrupted a parade and knocked him over. The festival is now a major tourist attraction, and participants throw hundreds of thousands of pounds of the ruby-red fruits a year.