The Longest Fence In The World, 5614 Km, Australia

Alternatives to fencing include a ditch (sometimes filled with water, forming a moat).
A balustrade or railing is a kind of fence to prevent people from falling over the edge, for example, on a balcony, stairway (railing system), roof, bridge, or elsewhere near a body of water, places where people stand or walk and the terrain is dangerously inclined.