World Amateur Radio Day is an annual observance held on April 18. It marks the anniversary of the establishment of the International Amateur Radio Union in 1925.
International Day for Monuments and Sites is an annual observance held on April 18. It was officially established by UNESCO in 1983, following the initiative of the International Council on Monuments and Sites (ICOMOS).
The International Red Cross and Red Crescent Movement was founded in 1863 in Geneva as the International Committee of the Red Cross. It is an international humanitarian movement that strives to protect human life and health. Many countries have their own Red Cross Societies that are part of the movement. For example, the Ukrainian Red Cross Society was founded on April 18, 1918.