Battlecruisers are a type of warship that combines the speed of a cruiser with the firepower of a battleship. They were designed to engage enemy ships while avoiding direct confrontation with heavily armed battleships. Typically, battlecruisers have lighter armor than battleships, allowing them to move faster and operate effectively in reconnaissance and hit-and-run tactics. The concept of battlecruisers emerged in the early 20th century, with notable examples like the HMS Invincible and SMS Von der Tann. They played significant roles in naval battles during World War I, but their vulnerabilities were highlighted in engagements such as the Battle of Jutland.