Stone Forts & Castles from around the World

So I'm a pretty huge stone fort & castle enthusiast, so huh...Let's talk about forts & castles, I guess stockades are alright too, I've seen some pretty cool ones but let's try to keep the spotlight on ones made of stone. Ever been to any cool ones or just know of one or more, post it.

I'll just start with Fort Jefferson, Dry Tortugas, Key West, Florida. Here's the google map link if you care to check it out.

https://www.google.com/maps/@24.6286549,-82.8707906,426m/data=!3m1!1e3

Here's a couple of neat one's in Bermuda.

Fort Hamilton

https://www.google.com/maps/@32.2949427,-64.7771227,198m/data=!3m1!1e3

And Fort St. Catherine

https://www.google.com/maps/@32.390734,-64.6746129,198m/data=!3m1!1e3

My personal favorite is Castilo de San Marcos in St. Augustine, Florida.

Singer Castle in the 1,000 islands.

Fort Mackinac, Mackinac Island, Michigan U.S.A.