An actor participates in a parade during a humor-themed festival in St. Petersburg, Russia, April 1, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)

Actors participate in a parade during a humor-themed festival in St. Petersburg, Russia, April 1, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)

Actors participate in a parade during a humor-themed festival in St. Petersburg, Russia, April 1, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)

People participate in a parade during a humor-themed festival in St. Petersburg, Russia, April 1, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)

Actors participate in a parade during a humor-themed festival in St. Petersburg, Russia, April 1, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)

An actor participates in a parade during a humor-themed festival in St. Petersburg, Russia, April 1, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)

An actress participates in a parade during a humor-themed festival in the street of St. Petersburg, Russia, April 2, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)

Actors participate in a parade during a humor-themed festival in St. Petersburg, Russia, April 1, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)

Children participate in a parade during a humor-themed festival in St. Petersburg, Russia, April 1, 2021. A humor-themed festival was held in St. Petersburg from April 1 to 4. (Photo: Xinhua)