People take part in activities at the Main Festival in Frankfurt, Germany, on Aug. 6, 2018. (Photos: Luo Huanhuan/ Xinhua)

People play with carousel at the Main Festival in Frankfurt, Germany, on Aug. 6, 2018. The four-day Main Festival, closed on Monday, witnessed children's carousel, fairground rides, games, tombolas and shooting galleries.

A girl chases a bubble at the Main Festival in Frankfurt, Germany, on Aug. 6, 2018. The four-day Main Festival, closed on Monday, witnessed children's carousels, fairground rides, games, tombolas and shooting galleries.

The Main Festival is held in Frankfurt, Germany, on Aug. 6, 2018. The four-day Main Festival, closed on Monday, witnessed children's carousel, fairground rides, games, tombolas and shooting galleries.