The cache is not at the posted coordinates.
Solve the puzzle and do the dance.
N 38° 47.ABC W 121° 18.DEF
Find the Day. Use the last digit.
A = Albert Einstein marries Mileva Maric +3
B = Japanese Soldiers Begin Six-Week 'Rape of Nanking' -6
C = Treaty Of Guadalupe Hidalgo Is Signed -2
D = Mount Rainier National Park Created +2
E = Washington delivers first inaugural address -5
F = Japan Attacks Pearl Harbor +1

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