In zoology, crepuscular refers to animals becoming active at twilight or before sunrise, as do bats and certain insects and birds. On this edition of B-Side we look at what humans do between the hours of 4 and 6 AM...and at dusk. First with a visit to a 24-hour-Walmart (talk about wildlife), followed by a trail walk at dusk. Liner Notes: "Who Needs Coffee When you Have Rowing?" Rob Sachs: Each day millions of people sputter around Southern California ebbing and flowing through interchanges on massive highways that stretch 5 lanes wide on each side creating quite a din. But at 4AM the streets of Marina Del Rey are quiet. Two female athletes have convened at a place called Mother?s Beach in pursuit of a little bit of early morning workout. B-Side's Rob Sachs met up with them. "Music Just Before Dawn" Molly Peterson: Some of the best times at a concert happen before -- and after -- the music itself. Molly Peterson and her friends have been going to the New Orleans Jazz and Heritage Festival every year for 10 years. They go to the late-night concerts that run into early morning. And over time, the way that they go hear music there has changed. Here's their story. "Magic Hour" Learka Bosnak: It is approaching the magic hour before dusk when all things are related. Walter Anderson said that. He was a southern artist. Photographers know what he was talking about. And so do the people who make movies. They say the light in the sky at this time of day is both unique and necessary to doing their work. Learka Bosnak reports. "Lighting the Empire State Building" David Johns: Around dusk most nights, New York's tallest skyscraper - the Empire State Building - turns colors. Some nights it's red, white and blue. Other nights it blushes pink. As you might guess, it's no small feat to light up a 100-story building. The thing is 200 times as tall as your average Christmas tree. Dave Johns met the man who runs the wires behind New York City's Tower Lights.

In zoology, crepuscular refers to animals becoming active at twilight or before sunrise, as do bats and certain insects and birds. On this edition of B-Side we look at what humans do between the hours of 4 and 6 AM...and at dusk. First with a visit to a 24-hour-Walmart (talk about wildlife), followed by a trail walk at dusk. Liner Notes: "Who Needs Coffee When you Have Rowing?" Rob Sachs: Each day millions of people sputter around Southern California ebbing and flowing through interchanges on massive highways that stretch 5 lanes wide on each side creating quite a din. But at 4AM the streets of Marina Del Rey are quiet. Two female athletes have convened at a place called Mother?s Beach in pursuit of a little bit of early morning workout. B-Side's Rob Sachs met up with them. "Music Just Before Dawn" Molly Peterson: Some of the best times at a concert happen before -- and after -- the music itself. Molly Peterson and her friends have been going to the New Orleans Jazz and Heritage Festival every year for 10 years. They go to the late-night concerts that run into early morning. And over time, the way that they go hear music there has changed. Here's their story. "Magic Hour" Learka Bosnak: It is approaching the magic hour before dusk when all things are related. Walter Anderson said that. He was a southern artist. Photographers know what he was talking about. And so do the people who make movies. They say the light in the sky at this time of day is both unique and necessary to doing their work. Learka Bosnak reports. "Lighting the Empire State Building" David Johns: Around dusk most nights, New York's tallest skyscraper - the Empire State Building - turns colors. Some nights it's red, white and blue. Other nights it blushes pink. As you might guess, it's no small feat to light up a 100-story building. The thing is 200 times as tall as your average Christmas tree. Dave Johns met the man who runs the wires behind New York City's Tower Lights.