At Lytle Park in Mattoon, Illinois you will find both a gigantic swimming pool and a diminutive oil well. Since the 1940s, kids have been jumping in the park’s cool blue water, and the well has kept on pumping.

Southern Illinois had an oil boom starting in the years leading up to World War II, and it was first discovered in the Mattoon area in 1940. By the peak of drilling in the late 40s, there were over 400 wells spread out over this part of the Illinois prairie. One of those wells, originally owned by an Oklahoma oil tycoon named Walter Duncan, was later operated by a couple of Texas drillers named Joe Blalack & Dick Walter. The Blalack & Walter Well No. 1 still plunges into Lytle Park day in and day out, drawing a stark contrast to the park’s enormous sparking pool, meticulous gardens and historic pine grove.

The well has been a boon for Lytle Park too; a portion of the revenue each year helps to keep the grounds and pool in good shape. You might miss the fenced-off area if you don’t look for it – it’s not what you think of when you imagine the towering rigs of the vast Texas or California oil fields. It’s little, almost cute. But since that first drop of black gold came out of the ground in 1946, this sturdy little rig has pumped over 100,000 barrels of oil.