We've visited 4 Corners a few times, usually in conjunction with Mesa Verde, when the kids were little. All part of the grand adventure of life! :)
We've also stood in the Northern and Southern hemispheres in Ecuador on one fun adventure as well. While also interesting, it wasn't quite as "interesting" as my shellback initiation back in the day on the Nimitz, when we crossed the equator somewhere off the west coast of Africa, while transitioning "without delay" from the Med to the I/O (one could argue that slowing down for a day for shellback initiation was a delay, but traditions are strong in Uncle Sam's Canoe Club).