This solstice (exact on June 20, at 11:46 PM PDT) is rather unique in that it will be accompanied by a nearly full moon. The full moon will be exact on June 21 (Tuesday) at 9:14 PM PDT.
What makes this event rare is that just before the moon turns full the moon will be crossing directly in front of the Galactic Center (GC) at 1:48 PM PDT.
Although the sun currently comes closest to the GC at the winter solstice, the moon is able to pass directly over the galactic center because its orbit dips several degrees above and below that of the earth. The orbit of the moon wobbles backwards relative to the movement of the moon. The wobble makes one full orbit of the earth every 19.5 years.