Have you ever driven along a highway and double took at something you saw in the corner of your eye? This is a common experience for those passing by Lake Berryessa, the seventh largest man-made lake in California.

Why? Well, it’s because it contains what looks like a giant hole. Out of use for many years because of the prolonged drought in California, it finally sprung into action again in early 2017, capturing the curiosity of a man with a drone.

To see what the inside of the hole looks like, check out the incredible video below:

Built against a 304-foot dam, Lake Berryessa is famed for its “Glory Hole” slipway, which is an incredible sight to see when it’s at full capacity, especially, as the video above demonstrates, when captured from the perspective of a drone.

To put the rarity of this video into context, when the drone captured this footage, it was the first time that the glory hole had been used in over a decade. So much rain fell in January and February of last year that the lake filled up in a matter of days.

The widest part of the hole measures a staggering 72 feet across and it travels a further 28 feet down. The water flowing into it is passed through a funnel, eventually draining out into Putah Creek.

The incredible footage was captured by YouTube user Evan K. While I’m not exactly sold on his decision to play AC/DC over it (I’d have preferred to listen to the rushing water), it’s impossible not to be mesmerized by it.