To find this cache you will first have to solve this simple
system of equations:
5x - 3y = 1573
3x + y = 2493
The correct x and y values are both 3 digit whole
numbers. If you come up with anything different, you're probably
using the wrong math.
The cache is located at:
N40 19.AAA W074 40.BBB
where AAA = x - clue, and BBB = y - clue.
At the posted coordinates you will find a memorial that has
exactly 3 different years on it. To get the clue, subtract the
oldest year from the most recent year.
The cache is a .50 cal ammo can that was started with goodies
that are out of this world, two TBs and an FTF prize.
Awards
1st to solve (sans the on-location final clue): PaperBlob
1st to find: TucsonThompsen
2nd to find: trowel32
3rd to find: TeamHopewell