An enormous sinkhole opened in the floor of the National Corvette Museum in Kentucky on Wednesday morning, swallowing several of the iconic muscle cars.

The sinkhole apparently began to open before 5:45 a.m., when there was no one inside the museum in Bowling Green, according to a statement posted on the museum’s Web site.

The museum said it was alerted to the sinkhole by an alarm company. Firefighters arrived to find a hole 40 feet wide and 25 to 30 feet deep, which had opened up in a large display area called the Sky Dome.

Photos from the scene showed at least two cars in the hole. In all, the museum said, eight Corvettes were affected — six owned by the museum and two that were on loan from General Motors. The GM plant that makes Corvettes is across the street from the museum.

The damaged cars included a 1962 model, a 1994 car listed as “PPG Pace Car,” a 1992 model that was the 1 millionth Corvette made, and a 2009 model that was Corvette number 1,500,000. Also damaged were a 1993 “40th Anniversary Corvette,” a 2001 Mallett Hammer Z06 model, a 1993 ZR-1 Spyder and a 2009 ZR1 “Blue Devil.”

The museum did not release a cost estimate of the damage Wednesday.

Bowling Green is in western Kentucky, an area with geology — full of karst — that has created an abundance of caves, springs and sinkholes.

Photos of the sinkhole were quickly disseminated on social media and television Wednesday morning, stunning Corvette enthusiasts.

“By golly, I’m looking at a picture now. Look at how deep it is. . . . Unbelievable. Ugh,” said Gary Mortimer, founder of the National Corvette Restorers Society, in a telephone interview with The Washington Post. He said many of the museums’ cars are the only ones of their kind left and would be difficult to replace.