"When the Moon Turns to Blood" refers to a phenomenon known as a lunar eclipse, specifically a total lunar eclipse. During this event, the Earth passes between the Sun and the Moon, causing the Earth's shadow to cover the Moon. As a result, the Moon can take on a reddish hue, often described as "blood red," due to the scattering of sunlight through the Earth's atmosphere. This reddish appearance is also called a Blood Moon. The phenomenon occurs several times a year, but not every lunar eclipse results in a Blood Moon. Cultural interpretations of this event vary, with some viewing it as a sign or omen in various mythologies and religions.