The Koppelpoort is a medieval gate in Amersfoort. The gate was built between 1380 and 1425 as part of the second city wall. The whole wall was completed around 1450. The gate was attacked in 1427 during the siege of the city, but this attack was repelled.
The gate was opened and closed every day by the appointed 'wheel-turners'. A minimum of twelve wheel-turners were collected morning and evening by several guards. It was an extremely dangerous task; if they did not begin walking simultaneously, then one could fall, dragging the rest along with often fatal results. Before the gate could come down, it had to be raised, to pull out the iron pins that held it in place. Only then could it come down. While the gate was going down, walking in the wheel grew ever easier and faster, and many people stumbled and broke their limbs. The koppelpoort was also never breached.
The Koppelpoort was given its current appearance during the restoration by Pierre Cuypers in 1885 and 1886. Among other things, Cuypers removed a step between the two gates and replaced it with a slope.
The latest restoration was completed in 1996. It was carried out very cautiously, and with respect for the old building materials.
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.