Antikythera Mechanism
Disputed. Proposed dates for construction range from c. 205 BC to the early first century BC. The Hellenic Ministry of Culture and Sports gives a working range of c. 150-100 BC. This is a separate question from the date of the shipwreck that carried it, which independent archaeological evidence places at c. 70-60 BC. - Cast and hand-cut bronze (gear wheels, plates, dial faces, pointers and axles), originally mounted in a wooden case with bronze cover plaques front and back