I'll start.
OK, a timing belt has teeth that mesh with the sprockets upper and lower, and also idler pulleys & tensioners. So lots of moving parts.
If the belt was to strip those teeth, all will stop turning.
Get the picture?
Kind of like losing your bicycle chain.
35520

Does the engine turn over but the timing belt doesn't move?
Have you tried with the accessory drive belts off? If an accessory has locked up that can "hold" things, too.

. T-Belt snapped.

. Tensioner problem; i.e. not adjusted properly or failure.

On your Accord, replace the T-Belt, water pump, and camshaft seals every 90,000 miles or 6 years, whichever comes first. Inspect the tensioner, before using it again.