The pelican eel is a rare fish that lives in the deep sea.

As the name suggests, an electric eel is a fish that can generate electricity.

An electric eel can generate electricity.

European eels can live in both freshwater and seawater.

Grilled Japanese eel is one of the traditional dishes in Japan.

Monopterus albus is a species of freshwater fish that lives in rice fields and marshes in Asia.

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