International Day for Monuments and Sites

The International Day for Monuments and Sites, also known as World Heritage Day, is an international observance held on April 18 each year around the world with different types of activities, including visits to monuments and heritage sites, conferences, round tables, and newspaper articles. Each year the International Council on Monuments and sites elects a theme, for example sustainable tourism in 2017 and rural landscapes in 2019.

Source: Wikipedia — International Day for Monuments and Sites (CC BY-SA 4.0)