Can you imagine an escalator with a moving ramp rather than steps?
Actually that's not what we see here at all, it's just the long exposure. Throw in some extra exposures for HDR processing and all sense of there being individual steps at all has been totally lost.
This style of image is easy to do at night where ambient light levels are low and long exposures are unavoidable. I am however looking forward to trying some of these techniques in strong daylight using neutral density filters.
Photo: Robert Rath, '366 Days of 2012, Day 272 - Escalator to Heaven'. 2s(+-2stops) f/10 ISO160 15mm hdr