Many retro-urban theorists maintain that high density is the key to urban prosperity.

FORBES: Megacities And The Density Delusion: Why More People Doesn't Equal More Wealth

Vincent, Merrill Garbus's Tune-Yards and Laura Marling, who added a cello and brass to her retro-folk sound, presented polished, high-concept chamber pop, as did Other Lives, who impressed with melodramatic baroque folk featuring strings, orchestral synths and vocal harmonies in support of the quietly charismatic singer Jesse Tabish.

WSJ: Coachella's Modern Mosaic | By Jim Fusilli

Too big to rely on air bags to cushion its fall as with previous Mars landers, Curiosity landed through an automated system of high-speed maneuvers, a supersonic parachute, eight retro-rockets and a set of "sky-crane" tethers that lowered the vehicle gently the last few feet to the ground.

WSJ: NASA's Curiosity Rover Lands on Mars

Boston collector Fred Sharf collects 1950s "high style" pieces designed by Van Cleef, but he's lately started buying "retro" pieces that were made with "ordinary stones" like citrine during the Depression and World War II.

WSJ: Collectors Focus on Jewels as Investments