Half and Full (photos via mrgeneko's flickr and michaelnyc's flickr)

Tonight is the first of the annual four Manhattanhenge events. Starting just around 8 p.m., the sun will align precisely with the Manhattan street grid, "illuminating both the north and south sides of every cross street of the borough's grid." The best spots to witness this—or rather, Instagram this—are at 14th, 23rd, 34th. 42nd, 57th, and several streets adjacent to them. "The Empire State building and the Chrysler building render 34th street and 42nd streets especially striking vistas," according to the American Museum of Natural History, or rather, Neil deGrasse Tyson, who coined the term.

Last year one street was closed off for the Manhattanhenge photo ops, but a rep at the AMNH told us this week if they do it again, it will be for the July event this year. Here's this year's dates:

Half Sun on the Grid
Thursday, May 29 8:16 P.M. EDT
Saturday, July 12 8:25 P.M. EDT

Full Sun on the Grid
Friday, May 30 8:18 P.M. EDT
Friday, July 11 8:24 P.M. EDT

deGrasse Tyson has pointed out that future civilizations may think our grid has "astronomical significance, just as we have found for the pre-historic circle of large vertical rocks known as Stonehenge. For Stonehenge, the special day is the summer solstice, when the Sun rises in perfect alignment with several of the stones, signaling the change of season." Though he adds that our days happen to fall near Memorial Day and Baseball's All Star break, so "future anthropologists might conclude that, via the Sun, the people who called themselves Americans worshiped War and Baseball."