Has US Learned anything since the WTC Building on February 26, 1993?

In 1993, A bomb rocks the World Trade Center in New York City. Five people are killed and hundreds suffer from smoke inhalation. What lessons has the U.S. Learned from this Horrific Occurrence? How much did it change our View on National Security? What Improvements have been made. Most people will Cite 9/11 as a setback in the Safety of Nation and National Security as a Whole. Talk to me!