I found these some of the most fascinating places in our trip to Israel. Herod was a paranoid individual -- always afraid that someone was out to kill him. So he had his wife and two sons killed, as well as countless others he considered to be threats. He is perhaps best known for the murder of the babies when he heard that a king had been born in Bethlehem (probably about 30 male children would have been killed).
One fact I find interesting is Herod feared there would be no one to mourn his death. So as he lay on his death bed, he had 1,000 people arrested in Nazareth, and gave the order that they be killed upon word of his death. That way, he felt there would be mourning. Fortunately the order was not carried out.
For all his lunacy, Herod was an engineering genius. He still baffles experts today as to how he did what he did.