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In the " Mystery Spot" in California, you will be able to experience what it's like to live in a gravity-free world, without ever leaving the earth.
Discovered in 1939, the area where Mystery Spot is located was originally marked for a summer cabin. But when people tried to chart the plot, their instruments started going out of control. Investigators that were sent to look into the strange phenomenon reported feeling light-headed as though some invisible force was trying to knock them off balance.  The decision to build the summer cabin was abandoned. Instead, the owners decided to build a structure that they called the Mystery Spot and open it to the public so that everyone could experience /t.
Over the years, thousands of tourists have flooded to the 150-square-foot area to see short people appear the same height as tall ones and experience leaning at impossihle angles without falling over.
So what causes these slrange things to happen? Some believe that it is because the area is an electromagnetic(电磁的) hotspot, while others are convinced that there are some unknown geological forces at work to contradict the law of gravity.
Rational scientists have thrown cold water on all these theories.  In 1981, Ray Hyman, a psychology professor, conducted a study on this and other similar mystery spots that have been " discovered" in various parts of the country. His conclusion? It's because of the way the structures have been constructed.
Though they appear to be normal structures, they are like funhouses, filled with floors that are not level, corners that are not squared and walls that are not vertical.
Some experts believe that mystery spots such as the one in Santa Cruz are a product of the Great Depression, when the only industry that was growing in America was entertainment.
What can we do in the " Mystery Spot" in California?

A．To experience what it is like to have no gravity. '

B．To make preparations to leave the earth for space.

C．To communicate with astronauts in space.

D．To look for answers to many mysteries.

What does the underlined word "it" refer to in Para.  2 ?

A．Charting a place with advanced instruments.

B．Being made light-hearted and happy by some force.

C．What it's like to have no gravity in a place.

D．Seeing short people grow tall.

What's the explanation of some rational scientists to the strange phenomenon?

A．The Mystery Spot islocated in an electromagnetic hotspot.

B．There are some unknown geological forces underground.

C．The Mystery Spot is a normal structure like funhouses.

D．The Mystery Spot was built in a special way,

After the Mystery Spot was built, it _________.

A．has become a spot where hot movies are made

B．has become a tourist attraction

C．has been a place where short people always go

D．has become a scientific research center