[jfengel]

As the other replies have pointed out, there aren't really undiscovered castles.

But I do recommend visiting Germany, where there are way, way more castles than you might expect. In particular I can recommend the "Castle Way" along the Neckar River. Every bend in the river has its own castle, just dozens and dozens of them.

Most are not especially dramatic. Many are just ruins; others are literally just people's homes now. Still, it's a little bit like a D&D fantasy world where there really are just castles everywhere. (And yeah, some of them have genuine dungeons.)

[stefanka]

We discussed a fun fact in the office lately: There is an estimated 25K castles in Germany (1) while there are only 13K Mac Donald’s in the U.S. (2)

(1) https://www.dw.com/en/does-germany-really-have-25000-castles...

(2) https://www.scrapehero.com/location-reports/McDonalds-USA/

[cuSetanta]

Lived in a small town along the Jagst river for a while, which joins the Neckar at Heilbronn. You get Castle Fatigue fairly quickly with how many castles there are around there. Its hard to care about the 15th castle you pass in as many minutes. And I grew up in Ireland, which itself has a lot of castle dotted around the place.

[WalterBright]

> Every bend in the river has its own castle

The purpose of those castles was to extract money from the river traffic.

[chrisco255]

More like living on a body of water was like having access to a highway. And while a lot of trade happened along a river, it's also a risk for invasion from armies and raiding parties, hence the need for protection.

[WalterBright]

Having lived in Germany for a while, and toured the castles along the Rhein, I was told by the tour guides that toll extraction was their purpose.

[digging]

Tour guides of historical sites are often completely or even willfully wrong about facts like this, but in a sense almost all castles exist to exert control over nearby resources so they're probably right.

[shiroiushi]

It's probably both. Rivers are convenient for transport, which means raiders can also target them since so much valuable stuff is transported that way. A castle is a sensible way (in those times) to put a protective force in place against the raiders. However, the castle and the people protecting river traffic need money, so of course that comes from tolls.

It's no different than any "protection racket" or police force: the money has to come from somewhere to offer protection, so some form of tax is normally used.

[chrisco255]

You don't really need a whole castle to collect a toll (just a gateway of some kind). You need a castle to protect a village from raiders.