The Styrian Armoury (Landeszeughaus) is the world's largest historic armoury and attracts visitors from all over the world. It holds approximately 32,000 pieces of weaponry, tools, suits of armour for battle and ones for parades.
Between the 15th century and the 18th century, Styria was on the front line of almost continuous conflict with the Ottoman Empire and with rebels in Hungary. In order to defend itself it needed troops and these troops needed equipment. The Styrian Armoury results from the resulting need to store large quantities of armour and weapons, and was built from 1642 - 1645 by a Tyrolean architect called Antonio Solar.
After about 100 years in use, Austrian empress Maria Theresia wanted to close down the armoury, as part of her centralisation of the defence of Austria. Nevertheless Styria petitioned for the ongoing existence of the armoury for both practical and sentimental reasons. Their petition was accepted and the Armoury was left intact, but largely decommissioned.
References:Celje Castle was once the largest fortification on Slovenian territory. The first fortified building on the site (a Romanesque palace) was built in the first half of the 13th century by the Counts of Heunburg from Carinthia on the stony outcrop on the western side of the ridge where the castle stands. It had five sides, or four plus the southern side, which was a natural defence. The first written records of the castle date back to between 1125 and 1137; it was probably built by Count Gunter. In the western section of the castle, there was a building with several floors. Remains of the walls of this palatium have survived. In the eastern section, there was an enclosed courtyard with large water reservoirs. The eastern wall, which protects the castle from its most exposed side, was around three metres thicker than the rest of the curtain wall. The wall was topped with a parapet and protected walkway.