Well, if you stand on a long straight road and look to the horizon, it appears the two sides meet. And “parallel” lines of longitude on the globe meet at the north pole. I think Einstein had some exotic spacetime geometry idea where “parallel” lines meet (can anyone confirm or deny, or was it another physicist), and lines of longitude on the globe is the analogy to help you think about it. Also, I think there is some axiom in Euclids geometry which cannot be proven or disproven from the others, but which is considered the most dubious, or was long considered provable but just not yet, which involves parallel lines, but I am not sure if it is equivalent to “parallel lines do not meet at infinity”. Again, someone else research or recall it and write up a report with citations for us. I may have just created 2 (false) urban legends: about Einstein and Euclid. And if so, I will take pride in it to my grave.