Equinox

When the activated ability resolves, determine whether the targeted spell would destroy a land if it resolved right then. If it would, then counter that spell. Otherwise, it is not countered, even if the spell could, under other circumstances, destroy a land.

Will not counter a spell which would destroy a land only if a choice is made.

The ability can target any spell, even one that would not destroy a land.

Equinox will not counter a spell that has a random chance of destroying a land.

Equinox will not counter a spell which would indirectly cause destruction of one of your lands.

Equinox will not counter a spell which requires sacrificing land when it enters or one that requires sacrificing land as part of the cost to cast it.