Fortified frontiers

Ditches, barbed wire fences, brick and stone walls are all means of building obstacles between two peoples, sometimes to keep one group in and sometimes to keep the other group out. The Great Wall of China, the Maginot Line, and the Berlin Wall are examples.

The USA is currently digging a ditch 1.5 metres deep and 4 metres wide near the main border crossing with Mexico at Tijuana to "address a security and safety concern".

1. Intra-continental divisions
2. Divided countries
3. Disturbance to wildlife patterns of movement

1. Divided geographic allegiance

1. Violence along internal borders
2. Social divisions
3. Illegal movement across frontiers

1. Loss of internal political borders

1. Reuniting countries
2. Managing divided cities
3. Fortifying frontier lines
4. Establishing frontier barriers

1. Barrier