1) Siege tower 
Helepolis (ἑλέπολις, English: `Taker of Cities`) was an ancient siege engine invented by Polyidus of Thessaly and improved by Demetrius I of Macedon and Epimachus of Athens for the unsuccessful siege of Rhodes, based on an earlier, less massive design used against Salamis (305–304 BC). The name was derived from `ελείν πόλει......
siege tower.
Siege tower.