Here is a delcaration from the return to earth of Appollo 11 when Neil Armstrong, Buzz Aldrin and Mike Collins did the first moon walk:
Notice the signatures of each of the astronauts:
And in answer to the routine "Where have you been?":
"What are you bringing back into the country?"
Moon rocks and moon dust samples! And we think it is cool when the kids bring back seashells!
A little known part of a customs declaration, and one that is more common when travelling by air or by sea, is the statement about possible diseases that may be brought into the country. The standard answers, of course, are mad cow disease, TB, yellow fever, malaria, and in certain years, H1N1 or SARS. With the moon being a brand new research field and one never before travelled, the customs officer has written in: "To Be Determined"
I will now have a whole new understanding of the questions when I am impatiently waiting in line for the chance to cash in on some deals across the border!