The entire reason that the ingame LtL universe is around is because of humans. InGen scientists were able to successfully clone and raise dinosaurs. On five islands worldwide, these animals were released, where the humans observed them, and planned to display them to the public. But unfortunately, disaster struck and the public islands were evacuated. Now, the Creators are still stumbling onto the islands.
The most recent sighting of Creators was when a ship almost crashed into Isla Nublar. When the ship first came into the area, the only visible part was the smoke, which many dinosaurs called "the flame-less fire". When the ship was within mere meters from the island, dinosaurs flocked to the coast to catch a glimpse of the god-like Creators. Those that did see the ship will most likely remember it for a long time.
Veterans, feel free to add the earlier encounters which are only whispered about now.