Ligaments are strong, flexible bands of connective tissue that connect bones to other bones at joints. They help stabilize and support the joints, allowing for a range of motion while preventing excessive movement that could lead to injury. These structures are made primarily of collagen, which gives them strength and elasticity. Common examples of ligaments include the anterior cruciate ligament (ACL) in the knee and the ligaments of the ankle, both of which play crucial roles in maintaining joint stability during physical activities.