Imperialism - https://www.youtube.com/watch?v=2PWWgIUdARA

State Expansion - https://www.youtube.com/watch?v=gxkjaClzxPU

Intro - https://www.youtube.com/watch?v=a48aJVCNNUE  

Fiveable - https://library.fiveable.me/ap-world/unit-6  

PDF - https://www.peoriapublicschools.org/site/handlers/filedownload.ashx?moduleinstanceid=42982&dataid=77358&FileName=unit%206%20at%20a%20glance.pdf