Mesozoic
Paleozoic era
Scientists believe the Cretaceous-Paleogene extinction event, or the plants dying at the end of the Mesozoic Era, was caused by a massive asteroid/comet impact. The theory suggests that the impact had catastrophic effects on the environment, including an impact winter, which prevented the plants from carrying out photosynthesis.
Well nobody does really know yet when that "period of time" was if it even happened.
Precambarian- When earth’s atmosphere formed Mesozoic- Ended with a massive impact Paleozoic- When oxygen-breathing organisms first thrived Cenozoic- Began about 65 million years ago Hope this helps! :)
Massive Development ended in 2005.
Massive Magazine ended in 1999.
a big event like a massive extinction ends an era.
Massive - TV series - ended on 2008-10-12.
Improvement Era ended in 1970.
Massive.
Here is one: A massive comet or asteroid appears to have ended the dinosaurs lives.