It's a terrible, terrible tragedy.
a terrible tragedy
When something very bad happens to other people, you can call the situation "a terrible tragedy". These are some examples of terrible tragedies:
- an earthquake
- a bombing
- a school shooting
The adjective "terrible" is an ungradable adjective, which means that you can't use words like "very" in front of it. The word "terrible" itself is already extreme on its own.