Eurasia is the largest continental area on Earth, comprising all of Europe and Asia. According to some models of the world, physio-graphically, Eurasia is a single continent. The concept of Europe and Asia as distinct continents dates back to antiquity, and is largely cultural, but their borders have historically been subject to change. For example, the ancient Greeks originally included Africa in Asia but classified Europe as separate land. Eurasia is connected to Africa at the Suez Canal, and the two are sometimes combined to describe the largest contiguous landmass on Earth, Afro-Eurasia.