Fortified line
line of troops and armament, fortified and set up to protect a high-value location during an armed conflict
Wagner Line
Great Wall of China
Peter the Great's Naval Fortress
Metaxas Line
Roman limes
King's Lines
Prince's Lines
Queen's Lines
Siegfried Line
Maginot Line
Eagle's Nests
Johnston's Line Archaeological Site
Santa Margherita Lines
Czechoslovak border fortifications
cordon
Alpine Wall
Molotov Line
Antonine Wall
Fortified Position of Liège
Ceuta border fence
line of Du Moulin
waterlines
Bilbao's Iron Ring
Hindenburg Line
Morice Line
Castles of Ancona
Border Line
Berlin Wall
Civil War defenses of Washington, D.C.
Atlantic Wall
Jamestown Line
Panther-Wotan line
hedgehog defence
Stalin Line
Gin Drinkers Line
Bar Lev Line
Kuban bridgehead
Vesting Holland
investment
National Redoubt