The Yeti of the Himalayas may be the most fascinating undiscovered creature. Many climbers claim to have seen the Yeti or its footprints, and local inhabitants of the mountains are convinced of its existence. Such well-known mysteries as the Yeti and less well-known mysteries as the Congo dinosaur and the Queensland tiger will no doubt be the source of much speculation for years to come.

The word "speculation" in the last paragraph is closest in meaning to