Megapixels aren't the be all and end all when it comes to photography (the sensor size and lens quality is more important) but they certainly don't hurt - and Canon just set the bar higher than ever with a new 250-megapixel APS-H sensor.
The APS-H refers to the physical size of the sensor: it's a little bit larger than the sensors on consumer DSLRs and a little bit smaller than the sensors in professional top-end models. In other words, Canon has done a clever job of packing all these megapixels into such a tiny space.
Open up a 250-megapixel photo on your computer and you can zoom and zoom and zoom into the tiniest of details. Take a video, and the frame size would be 30 times that of 4K - a rather impressive benchmark.
You'd need to pair this with a seriously advanced (and expensive) lens to take advantage of all those megapixels but on a technical level it's another notable breakthrough in the world of digital photography.
With a picture size of 19,580 x 12,600 pixels, Canon says you could distinguish the lettering on the side of an aeroplane from about 11 miles away. According to the company the sensor uses "enhanced signal-processing technology" to reduce the noise you would otherwise see on such a big image.
It's likely to be a long time before a sensor like this makes it into your prosumer digital camera, but Canon says the new technology could be used for "specialised surveillance and crime prevention tools, ultra-high-resolution measuring instruments and other industrial equipment, and the field of visual expression."