Madrid
I read a ~500 page book on the history of Spain and it didn't mention Madrid once.
That's wild.
To be fair, the focus of the book is the history of Islamic Spain. Then again, Madrid was founded by Emir Muhammad I of Cordoba. In fact, the word 'Madrid' itself may be of Arabic origin, derived from majrit (مجريط) meaning 'stream'. (In this case, it would be a reference to the River Manzanares.)
It kind of reinforces, at least for me, the idea that Madrid tends to fly under the radar.
I mean it is an exceptionally elegant city ...
... but tends to live in the shadow of those other two beloved capitals of Western Europe: Rome and Paris.
There is an abudance of striking architecture.