Keep Your Ear to the Ground

Etymology:

• In 19th century when Hollywood movies became much popular, there was a scene in one of the action movie in which a local American puts his ear to the ground to tell if the horses are coming near. Though the horses are not near but he could perceive vibrations of hooves of horses from the ground. The phrase became much popular in the 19th century, if you pay great attention to something, or you have knowledge of the world around then you “keep your ears to the ground.