Curious by the Sharptooth's comment, Steven decided to sniff the air. If it wasn't for the historical simulators he had been through many times, he wouldn't have been able to identify the strange smell. He knew what it was, but didn't want to believe it.
"What is it?" asked Elizabeth.
Steven whispered in her ear, "Light air pollution, most likely from a city."
"But that can't be possible. Can it?"
"Only one way to prove or disprove it." Steven then saw the exit of the cave. He decided to pick up the pace, followed by Elizabeth, then Littlefoot and the others.
As soon as Steven got out of the cave and saw the Great Valley, he was speechless at what he saw. When Elizabeth saw it, she was just as shocked as he was and could only say, "That's not possible." When Littlefoot saw it, he was more shocked than either of them.
What they saw was not the Great Valley, but a city. A city that hadn't been here for thousands of years. Since they were on a big hill at the Great Wall (which had barely changed), they could see the downtown area (the center of the "Great Valley"), which had many tall buildings. One building was much taller than all the others, and was shaped like a steep-sided pyramid (imagine the Transamerica Building in San Francisco, only twice as tall). Outside of downtown, the city was different. There were smaller buildings, along with many parks, seen from the hill as large patches of green land. At the edge of the city were many suburban houses. There weren't many of these houses near the hill. Up on this hill there was one street that passed by in front of them, but it looked like it hadn't been used in years.
"What happened?" asked Littlefoot, still very shocked.
"I don't know," replied Steven. "I just don't know."