A 240 step staircase in Crestwood Park, Kirkland, WA. https://www.wta.org/go-hiking/hikes/crestwood-park-trail
A lap consists of running from the bottom to the top, and back.
Gonna check this out today, not expecting any records but announcing my intention just in case :)
Only ended up doing 16 laps but still got a great workout in. The stairs get some decent use so if you were going for the record, I'd pick a time other than the weekend. It's also hard to go fast downhill when the steps are wet, so avoiding rainy days would be helpful too.