(The Center Square) - Terror struck America on Sept. 11, 2001, when 19 al-Qaeda hijackers seized four Boeing jets and turned them into missiles, killing almost 3,000 people.

The hijackers arrived in the U.S. on tourist visas with cash and travelers checks they got in the Middle East. They enrolled in flight schools.

Originally published on thecentersquare.com, part of the BLOX Digital Content Exchange.