<h1>Barrier</h1>
<p>These are used to describe barriers and obstacles that are usually involved by traveling. See the page Barriers for an introduction on its usage.
</p>
<p>[<b>barrier</b>=<b>cable_barrier</b>]<br>A road side or median barrier made of steel wire ropes mounted on weak posts.</p>
<p>[<b>barrier</b>=<b>city_wall</b>]<br>A fortification used to defend settlements in ancient to modern times.</p>
<p>[<b>barrier</b>=<b>ditch</b>]<br>A man made ditch or trench to prevent access to the other side.</p>
<p>[<b>barrier</b>=<b>fence</b>]<br>A
 freestanding structure designed to restrict or prevent movement across a
 boundary, generally distinguished from a wall by the lightness of its 
construction.</p>
<p>[<b>barrier</b>=<b>guard_rail</b>]<br>A rail, typically metal, designed to keep vehicles within their roadway and prevent dangerous collisions</p>
<p>[<b>barrier</b>=<b>handrail</b>]<br>A rail designed to be grasped by the hand so as to provide stability or support.</p>
<p>[<b>barrier</b>=<b>hedge</b>]<br>A line of closely spaced shrubs and tree species, which form a barrier or mark the boundary of an area.</p>
<p>[<b>barrier</b>=<b>kerb</b>]<br>A stone edging to a pavement or raised path.</p>
<p>[<b>barrier</b>=<b>retaining_wall</b>]<br>A structure that holds back soil or rock from a building, structure or area.</p>
<p>[<b>barrier</b>=<b>wall</b>]<br>A
 freestanding structure, designed to restrict or prevent movement across
 a boundary, typically made from solid brick, concrete or rocks, and 
almost always built so that it is opaque to vision.</p>
