At No. 4, we take you into a room that very few are ever allowed in.
It's a cold blast from the past inside the Houston Public Library's vault. You need gloves to handle the books.
Some are from the 15th century. One book in particular was printed on calf skin paper. Another one was a Koran from the 1800s, written in gold.
Among the other treasures were old maps, the first books of Texas, and children's books like "Mother Hen."
At No. 3, we go to a place that we had to swear to keep secret: The Houston Museum of Natural Science storage facility.
Curator Dirk Van Tuerenhout gave us a rare tour.
"This is a real adult human being," Van Tuerenhout said as he took out a shrunken head of a tribe warrior from Ecuador. He was beheaded by a rival tribe.
"They would cut the skin off, peel it off the skull. At that point you only have skin and hair. And then you boil it. You boil it for a long time and put hot sand and pebbles, and it shrinks it to the size you see here," Van Tuerenhout said.
In another cabinet, Van Tuerenhout showed us something never seen by the public.
"These feather works are mostly kept here in the dark, because light will make these feathers fade," Van Tuerenhout said.
The museum's Amazonian collection is one of the largest in the world. Van Tuerenhout showed us earrings with more feathers.
"This is a tooth from the largest rodent in the world," he said.
Another priceless item we found was a centuries old samurai dagger, which is one of only a few in the world.
At No. 2 of places you can't go, we take you to where bugs are bred, spiders are fed and stick insects like to play.
We get a rare tour where cameras are never allowed. The room is sealed by the order of the USDA at the Houston Zoo's bug exhibit.
Very few people see what we were able to experience. The larvae of an elephant beetle, now a 1-year-old, buried in the dirt was unearthed for us.
We also met a venomous, salmon pink, bird eater tarantula named Carmen.
The No. 1 place you can't go is a room deep inside NASA.
"Rocks from outer space actually tell the story," Andrea Mosie said.
We suited up to get in the Lunar Lab, and when we did, we saw the moon rocks.
Scientists are using it to try to unlock the secrets of the universe.
"So when the astronauts actually picked up this sample, their thought was that's why we came here. This is what we were looking for," Mosie said.
Behind the big vault, we found the mother lode of moon rocks from all six Apollo missions.
All of the nation's priceless moon treasures, nearly 800 pounds, kept in nitrogen chambers are heavily documented and even more heavily guarded.
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