They lived there 30 years until Gen. Lee resigned his commission to avoid fighting against his home state. The Lees vacated the property in 1861. Union troops occupied it and 200 acres were set aside to bury fallen Union soldiers. Today over 250,000 war dead are buried there. Now of course, it is known as Arlington National Cemetery .
Nobody seems to remember when and why it was built.
Years ago miners who worked nearby used it. Today you can get to it on dirt roads. It has a world-wide cult following now, with people from all over the world calling and visiting it. A mechanical engineer invented a device in the 1870's to oil train wheels while the train kept running. It was called a lubricator.