I think you don't know that there are still countries being colonized and how long the colonies lasted
the british empire was once known as the empire on which the sun never sets, because wherever the sun went there was a british colony
maybe you also don't know what happens to the people who were part of the country before becoming a colony too
bombs are thrown to show its power over another country, the usa knows very well what to do to show that its imperialism is the strongest Hiroshima and Nagasaki too