system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happened to all the businesses that were in the WTC pre-9/11 and who will occupy the new World Trade Center?
gpt
Any of the businesses in the WTC that were hit by 9/11 are still up and running. Any tenant of the WTC would not be some mom and pop shop who had their whole livelihood wiped out. All companies that size have extensive disaster recovery plans, off site data centers, business disruption plans that are communicated to all the employees, in some cases they would have a backup office space for key employees to go to for exactly that scenario. 

Then they would have to find a new office space, but 9/11 certainly did not put an end to any of the businesses who were tenants of the WTC.