Some tourists got an unexpected surprise in the Haight on Sunday morning as their tour bus unexpectedly caught on fire.

Around 10:35 a.m., Sunday morning, a double-decker Big Bus San Francisco tour bus burst into flames as it drove down Haight Street near Golden Gate Park. The Chronicle reports that, thankfully, nobody was injured.

Eyewitnesses told both the Chron and Hoodline that the driver wasn't even aware that the bus had caught on fire until passersby got their attention. "A woman who works at Sunshine [Wine and Liquor] and a homeless man chased the bus down the street to alert the driver," neighbor Katherine B. told Hoodline.

"It was smoking, then literally fire started coming out. That's when I thought I have to run. We were running telling them, 'Stop!' I said, 'Come on, get out of there,'" said Senait Weldetensae, who owns Sunshine.

Paramedics who arrived on the scene evacuated the bus and firefighters were able to quickly put out the flames, but by then the entire bus had been engulfed. The cause is currently unknown.

This is, by the way, the second time in two years that a double-decker bus like this has spontaneously caught fire.

Reader Martina B. passes on this photo of the aftermath. That bus is definitely going to need a new paint job.