Over 50 people were killed and more than 500 injured when a gunman opened fire on crowds at a music festival in Las Vegas on Sunday.
You never truly know how you'll cope during an attack or terrorist situation and hopefully you'll never have to experience it.
But one of the ways we can learn and be better prepared for a worst case scenario, is by listening to people who have been through similar situations.
A reddit thread recently asked people who had survived terrorist attacks for what they wished they'd known prior to the event.
Here are a few of their responses.
A user who said they survived the summer camp shooting on the island of Utøya, Norway in July 2011 had this to say.
Keeping you spirits up is also a good idea if you are trapped for a long period of time.
Get away from the area.
This user says they were at the Boston Marathon when the bomb went off in 2013, this is what they had to say.
Remaining calm is essential.
Learn some first aid, get to safety and help others get to safety too. Don't just stand there filming it on your mobile phone.
This user says they were in the vicinity of both the Paris attacks in 2015, and the the Brussels bombing in 2016 - this is what they had to say.
Even if it's just saving the phone numbers of your embassy while abroad, preparation will always pay off.
Often though, the situation is simply out of your control.