Stuff is falling off cliffs all down the NorCal coast after drenching rains have saturated the already unstable sand and rock embankments that have at tendency to break apart this time of year. So be careful out there!

On Monday, a World War II-era structure — likely one of the many gun batteries or something similar that were built in the lead-up to the U.S. entry into the war, when there was a fear of a Japanese naval attack on San Francisco — fell off its perch at Fort Funston and dropped down around 200 feet to the beach.

"Beachcombers at Fort Funston will share the beach today with a WWII military structure undermined when saturated bluff sand slid onto the beach," writes the Golden Gate National Recreation Area's Twitter account. "Thanks to [the SFFD] for safety assistance.  Visitors are encouraged to follow postal trailhead signs and be attentive to surroundings."

Like multiple other military bases and forts around the Bay, Fort Funston was deactivated back in the 1960s and was taken over by the National Park Service.

And while this "WWII military structure" was like a bunker or battery, we still don't know exactly what it is — or if curious passersby can now look inside it.

Per the Chronicle, Fort Funston "was established as a military outpost in 1900, but the first structures began going up in 1917. During the Cold War, the site housed one of the Bay Area’s 12 missile defense installations."

Fort Funston features some infamously unstable bluffs and cliffs, one of which gave way in February 2019 while a woman and her dog were hiking on it, burying the woman alive. The woman's body was buried and remained missing for over a month before ultimately being discovered.

Earlier on Monday, an enormous boulder landed on Highway 1 just down the coast, due to saturated bluffs and cliffs. And rock- and landslides are ongoing all through this area, so beware.