The Wieliczka Salt Mine was built in the 13th century and produced table salt continuously until 2007, as one of the world's oldest salt mines still in operation. From its beginning and throughout its existence, the Royal mine was run by the Żupy krakowskie Salt Mines.
The mine's attractions include dozens of statues and four chapels that have been carved out of the rock salt by the miners. The oldest sculptures are augmented by the new carvings by contemporary artists. About 1.2 million people visit the Wieliczka Salt Mine annually.
The Wieliczka salt mine reaches a depth of 327 metres and is over 287 kilometres long. In 1978 it was placed on the original UNESCO list of the World Heritage Sites. Even the crystals of the chandeliers are made from rock salt that has been dissolved and reconstituted to achieve a clear, glass-like appearance. It also houses a private rehabilitation and wellness complex.
References:The ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.