How does the dream of the sun never sets in Britain come true through poetry?

Britain finally established a coveted colonial empire, whose sphere of influence spread almost all over the world, and realized the "dream that the sun never sets". There is a poem that says: Land is the place where Britain was founded, and the whole world can see this country. The red ones are all British territory, and the others are gloomy. The colonies of the British Empire are all over the world, so that the British flag can be seen wherever there is sunshine on the earth, so it is called "the sun never sets".