Zelená Hora ('Green Mountain') is a castle on the north side of Nepomuk. The church has been a pilgrimage site since the 1700s. There was originally a fortified church built in the late 14th century. It was forfified probably in 1419-1420 during Hussite Wars.
The current castle was built in 1669-1696 by Šternberk family in Baroque style. In 1819 Václav Hanka's forged medieval Manuscript of Zelená Hora, a counterpart to his Manuscript of Dvůr Kralové, was allegedly discovered in the castle and not exposed as a literary hoax, by Atheneum, until 1886.
The Amphitheatre of the Three Gauls was part of the federal sanctuary of the three Gauls dedicated to the cult of Rome and Augustus celebrated by the 60 Gallic tribes when they gathered at Lugdunum (Lyon). The amphitheatre was built at the foot of the La Croix-Rousse hill at what was then the confluence of the Rhône and Saône.
Excavations have revealed a basement of three elliptical walls linked by cross-walls and a channel surrounding the oval central arena. The arena was slightly sloped, with the building"s south part supported by a now-vanished vault. The arena"s dimensions are 67,6m by 42m. This phase of the amphitheatre housed games which accompanied the imperial cult, with its low capacity (1,800 seats) being enough for delegations from the 60 Gallic tribes.
The amphitheatre was expanded at the start of the 2nd century. Two galleries were added around the old amphitheatre, raising its width from 25 metres to 105 metres and its capacity to about 20,000 seats. In so doing it made it a building open to the whole population of Lugdunum and its environs.