How to do a recessed manhole cover! #landscaping #landscaper #manhole #manholecover #drain #drains #diy #gardenproject #gardendesign | Macclandscapes

The Manhole Cover That Almost Reached Space Enter the high-speed mystery of Pascal‑B. In August 1957, during the Operation Plumbbob nuclear test series at the Nevada Test Site, a massive steel cap (commonly referred to as a “manhole cover”) was blasted off a shaft by a shock-wave caused by the underground detonation. Camera footage captured the cap only for a single frame—leading to speculative estimates that it reached velocities exceeding 60 km/s (≈216,000 km/h)—many times Earth's escape veloc

Operation Plumbbob’s “Manhole Test” (officially known as Pascal-B) was a U.S. nuclear test conducted in 1957 at the Nevada Test Site. It involved detonating a small nuclear device in a deep underground shaft capped with a steel manhole cover. The goal was to study high-energy explosive effects and containment methods. The test unintentionally launched the steel cap at an extraordinary speed, possibly exceeding Earth’s escape velocity (~11.2 km/s), making it one of the fastest manmade objects. Wh