People pose for photos with a 3D chalk drawing of a flying plane during the Chalk Howard Street Festival in Chicago, the United States, July 20, 2019. The Chalk Howard Street Festival attracts the internationally-renowned 3D street artists, local 2D chalk artists as well as emerging artists. (Xinhua/Joel Lerner)

Children chalk drawings during the Chalk Howard Street Festival in Chicago, the United States, July 20, 2019. The Chalk Howard Street Festival attracts the internationally-renowned 3D street artists, local 2D chalk artists as well as emerging artists. (Xinhua/Joel Lerner)

Artists chalk their drawing during the Chalk Howard Street Festival in Chicago, the United States, July 20, 2019. The Chalk Howard Street Festival attracts the internationally-renowned 3D street artists, local 2D chalk artists as well as emerging artists. (Xinhua/Joel Lerner)

An artist chalks a 3D snail drawing during the Chalk Howard Street Festival in Chicago, the United States, July 20, 2019. The Chalk Howard Street Festival attracts the internationally-renowned 3D street artists, local 2D chalk artists as well as emerging artists. (Xinhua/Joel Lerner)

An attendee chalks her own drawing piece during the Chalk Howard Street Festival in Chicago, the United States, July 20, 2019. The Chalk Howard Street Festival attracts the internationally-renowned 3D street artists, local 2D chalk artists as well as emerging artists. (Xinhua/Joel Lerner)

A man poses for photos with a 3D chalk drawing during the Chalk Howard Street Festival in Chicago, the United States, July 20, 2019. The Chalk Howard Street Festival attracts the internationally-renowned 3D street artists, local 2D chalk artists as well as emerging artists. (Xinhua/Joel Lerner)