East and west era of exchange
https://drive.google.com/file/d/1HQSOBppOeDxI93SzTy6v2rY3htwTav7p/view?usp=drivesdk
Posts
River valley civilizations
https://docs.google.com/presentation/d/1HInfNbf6ozFSYla-lgC6Jlc-ldCdgP7H/edit?usp=drivesdk&ouid=112974653976237350032&rtpof=true&sd=true
