Global warming, coupled with changes in land use, such as deforestation, or extensive terracing, increases the risks.

UNESCO: 83e

The whitewashed farmstead sits above terracing of fruit trees, and is surrounded by neat lawns bordered by a kaleidoscope of roses.

BBC: Mini guide to rural Ibiza

But the crush was immense in the passageway and on the stairway which took fans out of the ground beyond the top of the terracing.

BBC: One minute's silence to mark Ibrox stadium disaster

Critics dispute this, arguing that the figures include abandonded terracing.

ECONOMIST: Bolivia