Please use the emergency stairs in case of a fire.

Due to the earthquake, the city declared a state of emergency.

I am an Earthling.

We are searching for extraterrestrial life.

The process of terraforming is part of transforming other planets into a habitable environment for humans.

Earth science is an important field of study for unraveling the mysteries of nature.

This is a historic building.

He is a famous historian and has written many history books.

He is majoring in history at university.

He is trying to hide his embarrassing past.