The Teatro Romano in Trieste was built in the first century BC and expanded in the second century AD. It had seats for from 3,500 to 6,000 visitors. It was probably built by the Trieste Quinto Petronio Modesto , prosecutor Emperor Trajan.
Over the centuries, the theater was left under the houses that were built above. Considered lost, it was identified in 1814 and unearthed in 1938 during the demolition of this part of the old city. The statues and inscriptions found in the excavations are kept in the San Guisto Castle.
Nowadays Teatro Romano is still occasionally used for outdoor summer shows.
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.