He devoted his youth to baseball.

I love period dramas.

The Paleogene period was a very important time in the history of the Earth.

I am planning to go to Inner Mongolia, an autonomous region of China, next week.

I have been to Outer Mongolia.

I have been to Chicago.

The Mesolithic is the era between the Paleolithic and the Neolithic.

The Bronze Age was an important period in human history.

The Azuchi-Momoyama period was a very important time in Japanese history.

The Azuchi-Momoyama period, also known as the Oda-Nobunaga period, was a very important time in Japanese history.