A man walks in Volksgarten in Vienna, Austria, Oct. 12, 2020. (Photos: Xinhua)

People walk in Volksgarten in Vienna, Austria, Oct. 12, 2020.

People walk in Belvedere Palace Garden in Vienna, Austria, Oct. 12, 2020.

People walk in University of Vienna Botanical Garden in Vienna, Austria, Oct. 12, 2020.

A woman walks in Volksgarten in Vienna, Austria, Oct. 12, 2020.

A pigeon stands among the fallen leaves in Volksgarten in Vienna, Austria, Oct. 12, 2020.

A man walks in Volksgarten in Vienna, Austria, Oct. 12, 2020.

A man walks in Volksgarten in Vienna, Austria, Oct. 12, 2020.

A staff member cleans fallen leaves in Belvedere Palace Garden in Vienna, Austria, Oct. 12, 2020.