Cathedral of SS Vitus, Wenceslas and Adalbert

The Cathedral SS Vitus, Wenceslas and Adalbert dominates Prague Castle. It is the largest and most important of Prague's places of worship and a spiritual symbol of the Czech state.
The Gothic Cathedral we see today is the third church to be built on the site - the first building to stand here was a Romanesque rotunda, then came a triple-nave basilica, and in 1344 Charles IV ordered work to begin on the construction of a Gothic cathedral. It took almost 600 years to complete, and wasn't consecrated until 1929.
The cathedral tower has a viewing platform providing stunning views of the cathedral, Prague Castle and the whole of Prague.

Royal Crypt

Just in front of the main altar stands the Royal Mausoleum, beneath which there is the Royal Crypt.

Chapel of St Wenceslas

The centrepiece of the entire cathedral is the wonderfully embellished Chapel of St Wenceslas housing the Tomb of St Wenceslas, the patron saint of the Czech lands.
In addition to religious services, the coronations of Czech kings and queens took place here. The Czech crown jewels are also kept here; they consist of the Crown of St Wenceslas (1346), the Royal Sceptre and the Imperial Orb (16th century), all made of pure gold and richly decorated with precious stones and pearls.

Crown of St Wenceslas

The Crown of St Wenceslas is made of 21 and 22 karat gold, weighs almost 2.5kg and is decorated with 96 unpolished precious stones. The ruby from the Czech crown is the largest on Earth. Of the nine largest sapphires on the planet, six are on the Crown of St Wenceslas. At the top of the crown there is a sapphire cross, in which is set a thorn said to come from Christ's crown of thorns.
Czech King and Holy Roman Emperor Charles IV had the crown made for his coronation. According to legend, he who places the crown on his head without rightful claim to the Czech throne will die within a year.

Sources: Czech Tourism