TL;DR: Viewed from above, the world has 24 hours. But it doesn't add up.
Though experiment: imagine yourself floating above one of the poles of the earth. Since I'm in the Northern Hemisphere I will use the North pole. Looking down at Noon Greenwich time, the sun is directly above Greenwich.
Now freeze the tableau and imagine yourself as an infinitely fast runner, starting at Greenwich and running West, across oceans and cities and all that stuff. As you run you wil cross time-lines: 11am, 10am,...until you reach the terminator between today and yesterday, 12:01 am. One more step puts you into yesterday. Leave this imaginary observer in place and return a new observer to Greenwich.
Observer 2, starting at noon Greenwich, starts running East, crossing timelines: 1pm, 2pm...11:59pm. One more step and your observer crosses into tomorrow. He/she/it is also face-to-face with observer #1. Two observers. Three days (Yesterday, Today, Tomorrow) all at the same point.
It doesn't work. Yet we live it daily.