The famous battle in which David killed Goliath took place in the Valley of Elah (1 Sam 17:4). Elah means terebinth, a tree commonly found in the area. The brook which runs through the valley is the Brook of Elah. It is a seasonal creek that runs dry for much of the year. The creek bed is shown below.
More pictures of the Valley of Elah are on the excellent Bible places website.