Digging a Hole

During the wonderful yet wacky weather yesterday I accomplished several chores and started a few others! What do you think this hole is for? It is about ten feet across and five feet wide at its widest. I dug the hole about 18 inches deep at its deepest point and about 12 inches in the upper part, but the digging is not yet finished! For a size a reference you can see a short handled shovel at the top of the picture. Can you guess what my mysterious pit is destined to be? There are clues on this site that may help you find out!