How did 9/11 change our physical world since 10 years ago?

How did 9/11 change our physical world since 10 years ago?

I interviewed my mom and she told me that people feel less secure in planes, even though airports have way better security systems now. She told me that when the planes crashed into the Twin Towers she was at work. My mom found out that the planes had crashed into the Twin Towers when one of her colleagues, who wasn’t working and was watching the news instead, told everyone there. She told me that she was really sad, and so was everyone at her workplace that day.