Memorial Day isn't the only thing to circle on your calendar this weekend, it's also a rare chance to check out Manhattanhenge.

That's when the sun lines up perfectly with the Manhattan street grid as it sets, and it only happens four times a year.

On Sunday you can see the half-sun version at exactly 8:12 p.m., and the full-sun version at the same time Monday.

The best viewing spots for this phenomenon are 14th, 23rd, 34th, 42nd and 57th streets.

Manhattanhenge returns in July.