Today, if it is clear, Manhattan [ http://en.wikipedia.org/wiki/Manhattan ] will flood dramatically with sunlight just as the Sun sets precisely on the centerline [ http://www.naturalhistorymag.com/city_of_stars/19_sunset_34th.html ] of every street. Usually, the tall buildings that line the gridded streets of New York City [ http://en.wikipedia.org/wiki/History_of_New_York_City ]'s tallest borough will hide the setting Sun. This effect makes Manhattan [ http://antwrp.gsfc.nasa.gov/apod/ap970408.html ] a type of modern Stonehenge [ http://www.britannia.com/history/h7.html ], although only aligned to about 30 degrees [ http://aleph0.clarku.edu/~djoyce/java/trig/angle.html ] east of north. Were Manhattan [ http://home.nyc.rr.com/jkn/nysonglines/ ]'s road grid perfectly aligned to east and west, today's effect would occur on the Vernal [ http://scienceworld.wolfram.com/astronomy/VernalEquinox.html ] and Autumnal Equinox [ http://antwrp.gsfc.nasa.gov/apod/ap030923.html ], March 21 and September 21, the only two days that the Sun rises and sets due east and west [ http://antwrp.gsfc.nasa.gov/apod/ap040320.html ]. If today's sunset is hidden by clouds do not despair [ http://antwrp.gsfc.nasa.gov/apod/ap040223.html ] -- the same thing happens every May 28 and July 12. On none of these occasions, however, should you ever look directly at the Sun.