Holi festival: Why people throw coloured powder at each other
12 March 2017 Last updated at 14:58 GMT
Millions of people around the world are celebrating Holi at the moment.
It's a Hindu spring festival that came from India but is now celebrated all over the world.
Holi is also known as the "festival of colours" or the "festival of love".
Watch Martin's video guide to it, including why people throw coloured powder at each other!