National colours are frequently part of a country's set of national symbols. Many states and nations have formally adopted a set of colours as their official "national colours" while others have de facto national colours that have become well known through popular use. National colours often appear on a variety of different media, from the nation's flag to the colours used in sports. Before World War I, they also served as the colors of different military uniforms for each nation. These are the national colours for countries or states that have limited or no recognition. colour in Chinese culture Some noted supranational organisations like the United Nations and the European Union have their own colours as part of their branding and marketing. They are usually taken from the organisation's flag. Although they do not have national sporting teams, the colours can be used for anything connected to the organisation, like associated bodies. United Nations: the recognisable blue helmets of the peacekeeping operations and the flags of associated UN agencies like the World Health Organisation, with the UN's light blue and white. European Union: the blue and yellow of the EU flag; uses include the blue European Health Insurance Card and the Blue Card for skilled immigration.