HBO (Aug. 21-22, 9 p.m. ET)
Spike Lee has subtitled his excellent four-hour film about Hurricane Katrina a “requiem” for New Orleans, and if the word at first suggests artistic overreach, it’s ultimately the right one. The film is as powerfully somber as it is thorough, with flashes of anger and despair, yet what may stay with you is the image of jazz musician and New Orleans native Terence Blanchard slowly playing his trumpet as he walks down a ruined, empty street. The third hour, dealing with homeless survivors displaced and flung across the country, is probably the most informative. But the whole thing has a beautifully measured pace, starting with the building chaos of storm and flood, then eddying into political and racial issues that will probably haunt not just New Orleans but the country for years.