On a budget, Strahov Monastery Library still earns its price.
~150 CZK; photo permit extra
The frescoed ceilings, globes and tiered gilt shelves are one of the most photographed interiors on earth, and the hilltop setting adds a city view and a monastery brewery. The honest catch: to protect the books you usually view the halls from the doorway behind a rope — you can't walk in — and a premium 'inside' photo permit is pricey. Manage that one expectation and it's still spectacular.