Why are the bottoms of amphoras always pointed?

Dr. dig responds:
An interesting question--an amphora is not the sort of thing you could just stand on a kitchen shelf! Amphoras were originally made by people who lived in the hot desert climates of the ancient Mediterranean. Amphoras, ancient jars for storage, were made with pointed bottoms so they could be stuck into the stand and not topple over. The shape was also space-saving and handy for storage in large numbers. Amphoras could be tightly packed--like sardines in a can--into the cargo compartments of ships bound for faraway markets. In countries where the ground was hard, not soft and sandy, amphoras were kept upright in metal tripods or stands. Bottoms up!