St. Cyril & Methodius Cathedral
The hiding place of the brave
The dying place of the courageous
I must say visiting the crypt is one of the heaviest experiences I've had.
When visiting Prague, there is so much to see, the centre is filled with tourists constantly. Nothing, however, will leave you more speechless, humbled and in awe and appreciation for what you have than this place.
I might be a little biased since I love history and have a little obsession with the Czechoslovak anti-fascist resistance, nonetheless, if you are in Prague, it would be a shame not to go here.