Isaiah 17

Isaiah 17 has probably the most straightforward unfulfilled prophecy we can find.

Isaiah 17:1

The burden of Damascus. Behold, Damascus is taken away from being a city, and it shall be a ruinous heap.

Damascus Syria is one of the oldest continuously inhabited cities in the middle-east and its modern day location hasn’t changed since ancient days.  It’s been conquered, but it’s never been destroyed.  So, this is most definitely to be accomplished in the future.
Isaiah 17:14

And behold at eveningtide trouble; and before the morning he is not. This is the portion of them that spoil us, and the lot of them that rob us.

As you can see, the destruction of Damascus will happen very suddenly.  Until recently, it would have taken a cataclysmic meteoric or volcanic event to completely destroy a city of this size in less than one day.  But now, a growing number of nations have the capability to perform destruction on this scale.
It also mentions that the destruction is in retribution to some aggressive action on the part of Syria against Israel, or more specifically, some sort of theft.

What it doesn’t say is important to consider as well.  If you read through the entire section, you’ll not see any mention of Christ.  It doesn’t mention the final ruler of the beast empire.  There are no clues at all on the timing of this event.