Esther 2:17

2:17 And the king loved Esther more than all the other women, and she met with his loving approval more than all the other young women. So he placed the royal high turban on her head and appointed her queen in place of Vashti.

Esther 5:14

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.

Esther 7:9

7:9 Harbona, one of the king’s eunuchs, said, “Indeed, there is the gallows that Haman made for Mordecai, who spoke out in the king’s behalf. It stands near Haman’s home and is seventy-five feet high.”

The king said, “Hang him on it!”