Imperialism is when a strong country takes control of a weak country.
Example 1: America took control of Hawaii. They literally just forced the Queen to renounce the throne and took control.
Example 2: Russia took control of Alaska. They bought Alaska for 7.2 million dollars.
Example 3: Spain took control of Costa Rica. Christopher Columbus stopped there and noticed how vulnerable they were. They decided to take control of it and it was really easy.
Example 4: France took control of Canada. They wanted to help colonize the area. Canada wanted the help of France and so when they tried to take over, Canada basically just gave themselves away.