On 18 April 1982, on the occasion of a symposium organized by ICOMOS Tunisia and a corresponding meeting of the Bureau in Hammamet, it was suggested that a day be established to celebrate the diversity of heritage throughout the world. From this idea, the International Day for Monuments and Sites was born. This project was approved by the Executive Committee who also provided practical suggestions to the National Committees on how to organize this day.

The UNESCO General Conference adopted the concept by passing a resolution at its 22nd session in November 1983 recommending that Member States examine the possibility of declaring 18 April each year “International Monuments and Sites Day”.

While many countries and regions have established heritage days, such as the European Heritage Days celebrated each year in September, the International Day for Monuments and Sites presents an opportunity for all ICOMOS National Committees to advocate their shared cause together on the same day.

At the revival of this day in 2001, ICOMOS President Michael Petzet and the Executive Committee proposed that the 18th of April be used by all Committees to draw attention to a particularly endangered type of cultural heritage in conjunction with the annual Heritage at Risk report. Every year a growing number of ICOMOS National Committees all over the world are holding special events on the 18th April.