Classic metal hemi-spheres are placed together and evaculated with a vacuum pump. They are very stongly held together by atmospheric pressure.
Similar demo can be done with two "dent pulling" suction cups.
A stool can be lifted by a sheet or rubber with a handle.
Questions:
Would this work on the moon? (ie. in a vacuum?)
What does the force depend on?
Would the force be higher or lower at the top of a mountain?
