The visual effect known as Manhattanhenge returns to New York City today. The Event—which was first named and noticed by Neil deGrasse Tyson—happens four times a year, twice with a half sun and twice with a full sun. It occurs when the sunset aligns perfectly with the city’s grid system, illuminating both the north and south sides of every cross street of the borough’s grid.

“It is a unique urban phenomenon in the world, if not the universe,” said  Tyson

Some PM storms may  interfere with the first event which will happen tonight, May 29, at 8:13 pm. During this event, half the sun is usually visible above the horizon while the other half is hidden below. For the best view of Manhattanhenge, you should be as far east as possible, but be sure to pick a street where the view is clear across to New Jersey and the Hudson River. The best views  are on 57th, 42nd, 34th, 23rd, and 14th street.

The same phenomena will unfold tomorrow, May 30, at about the same time.

If you’re not in town and/or if inclement weather obstructs the view this month, you’ll have another chance to see the phenomena in July. The next event happens on  July 12, at 8:20 pm.