"Abatis consisting of trees lying parallel to each other with the branches pointing in the general direction of approach and interlaced. All leaves and small twigs should be removed and the stiff ends of branches pointed." — Moss, 1914

Abatis

"Abatis consisting of trees lying parallel to each other with the branches pointing in the general direction…

"A formidable obstacle against cavalry consists of railroad ties planted at intervals of 10 feet with tops four and a half feet above the ground, and connected by a line of rails spiked securely to each." — Moss, 1914

Cavalry obstacle

"A formidable obstacle against cavalry consists of railroad ties planted at intervals of 10 feet with…

"They are usually made in sections of manageable length chained together at the ends." — Moss, 1914

Cheveaux de frise

"They are usually made in sections of manageable length chained together at the ends." — Moss,…

Remains of the circular walls round towns and palaces, which are known under the name Cyclopean, exist at the present day. These are found both in Greece itself and in many of the Greek colonies, as in Italy and Sardinia. Such walls consist of gigantic polygonal blocks of stone, the corners of which fit accurately into one another. Other structures of this kind consist of regular blocks of equal height. Both kinds are constructed entirely without mortar.

Cyclopean Masonry

Remains of the circular walls round towns and palaces, which are known under the name Cyclopean, exist…

A fire door is a type of door or movable barrier used as part of a passive fire protection system within buildings to prevent the spread of fire or smoke between separate sections. It is usually the only means of allowing people to pass through a fire resistant wall.

Fire Door

A fire door is a type of door or movable barrier used as part of a passive fire protection system within…

A thin, human-constructed barrier which separates two pieces of land or a house perimeter

Wire Fence

A thin, human-constructed barrier which separates two pieces of land or a house perimeter

A guard over each wheel of a motor vehicle, for example, that is shaped and positioned so as to block the splashing of water or mud.

Vehicle Fender

A guard over each wheel of a motor vehicle, for example, that is shaped and positioned so as to block…

"A fraise is a palisade horizontal, or nearly so, projecting from the scarp or counterscarp. A modern and better form consists of supports at 3 or 4 feet interval, connected by barbed wire, forming a horizontal wire fence." — Moss, 1914

Fraise

"A fraise is a palisade horizontal, or nearly so, projecting from the scarp or counterscarp. A modern…

A structure that can be swung, drawn, or lowered to block an entrance or a passageway.

Fencing Gate

A structure that can be swung, drawn, or lowered to block an entrance or a passageway.

Hadrian's Wall is a stone and turf fortification built by the Roman Empire across the width of what is now northern England. Construction began in 122 AD.

Hadrian's Wall

Hadrian's Wall is a stone and turf fortification built by the Roman Empire across the width of what…

"Palisades should be planted to incline slightly to the front. As little earth should be disturbed in digging as possible, and one side of the trench should be kept in the desired plane fo the palisade." — Moss, 1914

Palisade

"Palisades should be planted to incline slightly to the front. As little earth should be disturbed in…

The modern Gothic parapet is a stone design of a wall-like barrier found on the edge of a roof or structure. This style includes tracery, a series of intersecting ribbed lines.

Modern Gothic Parapet

The modern Gothic parapet is a stone design of a wall-like barrier found on the edge of a roof or structure.…

The modern Gothic parapet is a stone design of a wall-like barrier found on the edge of a roof or structure. This style includes tracery, a series of intersecting ribbed lines.

Modern Gothic Parapet

The modern Gothic parapet is a stone design of a wall-like barrier found on the edge of a roof or structure.…

A pile of sandbags.

Sandbags

A pile of sandbags.

"An abatis formed by felling trees toward the enemy, leaving the butt hanging to the stump, the branches sharpened, is called a slashing." — Moss, 1914

Slashing

"An abatis formed by felling trees toward the enemy, leaving the butt hanging to the stump, the branches…

"In the high entanglement the stakes average 4 feet from the ground, and the wiring is horizontal and diagonal." — Moss, 1914

High wire entaglement

"In the high entanglement the stakes average 4 feet from the ground, and the wiring is horizontal and…

"An ordinary barbed-wire fence is a considerable obstacle if well swept by fire. It becomes more formidable if a ditch is dug on one or both sides to obstruct the passage of wheels after the fence has been cut." — Moss, 1914

Wire fence

"An ordinary barbed-wire fence is a considerable obstacle if well swept by fire. It becomes more formidable…

The Yale Fence, which ran along on College in front of Old Brick Row, was a favorite of many generations of students. Plans for new buildings led to its demise in 1888. The Yale Fence Club was named in its memory. The fence currently lining Old Campus also evokes the old fence.

The Old Fence at Yale

The Yale Fence, which ran along on College in front of Old Brick Row, was a favorite of many generations…