A Hyper-power is a state that dominates all other states in every sphere of activity[citation needed]. A hyperpower is traditionally[citation needed] considered to be one step higher than a superpower. The Roman Empire, Mongol Empire, Ottoman Empire and the British Empire have all been thought to be Hyper-powers. In a modern context, hyperpower has been used to describe the United States' position as the lone superpower since the collapse of the Soviet Union in 1991.