One of the most impressive things found in this period was the Astrolabe of Antikithyra. Some sponge collectors found it in 1901 near the Antikithyra island. In the Greek research centre 'Demokritos' professor Derek de Solla Piere (from Yale university) and Har. Karakalos examined it with X-rays and found an amazingly complex construction. It is the most complex mechanical construction until 1200 A.D.!