Space Aliens
This was a simple dream with little detail. The first phase opens in the saucer space ship of some Space Aliens. They have launched a huge rain of fire over the entire Earth because they are unhappy that the reign of the Dinosaurs suppresses development of the Class of animals to which they belong. They are certain their class will survive the disaster and thrive while the Dinosaurs will become extinct.
The second phase opens in the present. Their attack did not work out well for the Space Aliens. The Dinosaurs were exinct, except for a vast number of predatory birds. Also, with the Dinosaurs gone, another Class of animals had arizen, Mammals, and proved to be even worse for their plans than the Dinosaurs had been, especially the humans. As a consequence, giant, ingelligent Cockroaches did not evolve on Earth.
Hotel, Convention Center
This was a very typical dream, except that I wasn't being pursued or searched for by anyone, though that has become less common than it had been for years.
The setting was in a very large Hotel / Convention Center, with a great amount of detail. It was quite crowded with people, and there were conventions displaying goods and artwork, as well as lectures. I was trying to return to the group of people with who I had been.
One problem was the usual. The building was huge and crowded. The elevators worked very oddly, taking me to the machinery rooms at the top down to the loading docks and basement storage - but they were not at all good at stoping on the floors I wanted to be on. In the last elevator I rode before awakening, there was a group of elderly women who belonged to some sort of club, but I'm not sure what the club was about. This elevator was descending to the basement.
Another problem was also the usual. Sections of the building would change geometry and purpose when out of my sight. They would be so different when I returned to that part of the building, it prevented me from finding my way.
Parkland
This dream, outdoors in a park or botanical garden, preceeded the Convention Center dream, but I have only the most vague impression of it and no detail.