Ramón's company is refreshing, because he sees no need to guide us, to educate us with over-talk.  He's mostly interested in what a couple from the states thinks about male-female relationships.  When we pass through a great stone chasm, he says, "Do you think women or men are more conscious of the other's desires?"

When we pass through a great forest of peculiar dwarf trees, dripping with brilliant green and orange bromeliads, he says, "I think that by age fifteen, women are eighty percent more responsible than men, but at age twenty-five, that starts to even out."

In the age of dinosaurs, North America was tropical; perhaps somewhat like this; rich and dense, wet.  Perhaps it was filled with creepers and climbers, dense vegetation, a dark understory, dense clouds.  That was 180 million years ago, and although the dinosaurs ruled, birds first spread their wings.  Small mammals appeared.  The first flowering plants bloomed.

Down a harrowing set of wooden steps, Ramón says, "the birth rate is out of control here."

here was no isthmus back then; North America was split in two by a great sea.  North America and South America each split from the two opposing super-continents, and even North America's two halves had originated from different places. 

Ramón says, "It's the Catholic bishops; they don't want sex education, they don't want birth control."

The eastern half was a stable island that existed in relative isolation for thousands of years. The west was associated with Asia, often banging back into it, letting the animals and plants of Asia step aboard. 

These halves of North America, and that chunk of South America - all distinct, bizarre places that we can only half imagine.  But then something fell from the sky, at an angle, around about where the Yucatan is now.  A chunk of old planet, long gone.  A different trajectory, and maybe it would have ended all life on earth. 

Instead, its angle of impact - facing towards North America, tore the biological membrane of the continent apart; causing massive fires, near complete destruction.  Within days, the globe looked from space like a ball of smoke, and most of the world was dead.