There are a number of natural processes that can form lakes.

This depression was filled by water, thus forming a lake.

Previously, the two lakes formed a single lake, as the name still suggest.

The fault dammed up the water to form a lake.

There are several minor and major dams along the river that form lakes.

Wetlands in the park were drained, and a dam was set up to form a lake.

The water was still there, forming a frozen lake three kilometers across.

Along the valleys there are several streams that form different lakes.

The huge excavations now form lakes and a nature reserve.

One may see high trees and a river which forms a lake at the entrance of a cavern.