11.   The nests are affixed to nearly inaccessible spots on cave walls and ceilings.

12.   Their paintings on the cave walls are thought to be the earliest reliably dated examples of art yet found in the Americas.

13.   They adorned themselves with necklaces, bracelets and beads, painted cave walls, and played drums and flutes.

14.   But then a flash flood swept through, forcing them to cling to the cave walls, barely able to move.

15.   Each of the spelunkers walked a short distance along the side of the cave wall with the aid of ropes.

16.   The cave walls were covered with blood, apparently smeared there by the killers.

17.   The designs are particularly elaborate and remain deeply etched in the cave walls.

18.   The drawings on the cave walls depict bow hunters taking aim at game, pregnant does and thunderbirds.