Esther 5:13-14

5:13 Yet all of this fails to satisfy me so long as I have to see Mordecai the Jew sitting at the king’s gate.”

5:14 Haman’s wife Zeresh and all his friends said to him, “Have a gallows seventy-five feet high built, and in the morning tell the king that Mordecai should be hanged on it. Then go with the king to the banquet contented.”

It seemed like a good idea to Haman, so he had the gallows built.