Work on St. Vitus's Cathedral started in 1344 and took another 600 years to finish. It contains the tomb of "Good King" Wenceslas and a fabulous Alfons Mucha window. There was a wedding starting, too, for extra fun - we didn't see the groom, but there was a groomsman holding the bouguet and the bride being photographed:
And this is just the rear of the Cathedral!
Interior elements of the Cathedral
And fabulous glass, stained and not...
Artist Alfons Mucha's window: