Carnuntum was a Roman Legionary Fortress and also headquarters of the Pannonian fleet from 50 AD. After the 1st century it was capital of the Pannonia Superior province. It also became a large city of 50,000 inhabitants. In Roman times Carnuntum had a history as a major trading centre for amber, brought from the north to traders who sold it in Italy; the main arm of the Amber Road crossed the Danube at Carnuntum. Its impressive remains are situated on the Danube in Lower Austria in the Carnuntum Archaeological Park extending over an area of 10 km² near today's villages of Petronell-Carnuntum and Bad Deutsch-Altenburg.
The remains of the civilian city extend around the village Petronell-Carnuntum. There are several places to see in the city: Roman city quarter in the open-air museum, palace ruins, amphitheatre, and Heidentor.
Some way outside the city was a large amphitheatre, which had room for about 15,000 spectators. A plate with an inscription found at the site claims that this building was the 4th largest amphitheatre in the whole Roman Empire.
Between 354 AD and 361 AD, Heidentor, a huge triumphal monument was erected next to the camp and city. Contemporary reports suggest that Emperor Constantius II had it built to commemorate his victories. When the remains of Carnuntum disappeared after the Migration Period the monument remained as an isolated building in a natural landscape and led Medieval people to believe it was the tomb of a pagan giant. Hence, they called it Heidentor (pagan gate).References:
Medvedgrad is a medieval fortified town located on the south slopes of Medvednica mountain, approximately halfway from the Croatian capital Zagreb to the mountain top Sljeme. For defensive purposes it was built on a hill, Mali Plazur, that is a spur of the main ridge of the mountain that overlooks the city. On a clear day the castle can be seen from far away, especially the high main tower. Below the main tower of the castle is Oltar Domovine (Altar of the homeland) which is dedicated to Croatian soldiers killed in the Croatian War of Independence.
In 1242, Mongols invaded Zagreb. The city was destroyed and burned to the ground. This prompted the building of Medvedgrad. Encouraged by Pope Innocent IV, Philip Türje, bishop of Zagreb, built the fortress between 1249 and 1254. It was later owned by bans of Slavonia. Notable Croatian and Hungarian poet and ban of Slavonia Janus Pannonius (Ivan Česmički) died in the Medvedgrad castle on March 27, 1472.
The last Medvedgrad owners and inhabitants was the Gregorijanec family, who gained possession of Medvedgrad in 1562. In 1574, the walls of Medvedgrad were reinforced, but after the 1590 Neulengbach earthquake, the fortress was heavily damaged and ultimately abandoned. It remained in ruins until the late 20th century, when it was partly restored and now offers a panoramic view of the city from an altitude of over 500 meters.