What are source of monument ​

Monuments are a primary source we can use to study the past. Sources created during the time period of study or by someone who lived through the time period of study are considered primary sources.

Monuments are a primary source of information about the past that we can use to learn more about it. Primary sources of history are those produced during the time period of study or by someone who lived during the time period of study.

The theory is land mass basically what they said.