Timing belt

If the belt isn't broken then you have a unique problem. Either the timing belt stripped some teeth, the lower timing sprocket key sheared, the crankshaft broke or the ring gear on the flywheel has stripped teeth or broken.

To maybe narrow it down, When you turn the key does the front drive belt turn like normal? If it does then it's either a bad lower sprocket/key or belt.
If it does not turn then it could be the ring gear or crankshaft.

Whichever it is you still will have to deal with the likely damage to the valves as that is an interference engine. By that I mean the valves extend far enough that if they are not moving in time with the crankshaft, the pistons will hit the ones that are open.