Right now about 70,000 people are hanging out in Memphis, Tennessee, to mark the 25th anniversary of the day a singer named Elvis Presley died. They're leaving love notes on Elvis's grave and flower arrangements shaped like hound dogs in the yard of his famous mansion, Graceland. Thursday night they'll light candles and march quietly past his grave.

What are they, nuts?

Jennifer Huget explains why, to lots of folks, Elvis will always be the King of Rock-and-Roll.

Life Before Elvis

To really understand why Elvis is such a big deal, you have to think about what the world was like before there was an Elvis. In the mid-1950s, most music on the radio was slow and boring, with gentle-voiced singers backed by syrupy orchestras. That was okay for grown-ups, but suddenly there was this new creature in America: the teenager.

The word "teenager" had been invented in the 1940s to describe young people who weren't quite kids, but weren't quite adults, either. Business people figured they could make lots of money if they could just come up with stuff that these kids would really like. All they needed was to find the right stuff.

What If They'd Named Him Vernon Jr.?

In 1953, an 18-year-old truck driver named Elvis Presley walked into a Memphis, Tennessee, recording studio that for about $3 would allow someone to record whatever song he wanted. Elvis recorded "My Happiness," a sweet, slow song, as a birthday gift for his mother, Gladys.

That recording session was the key to Elvis's future -- and rock-and-roll's. The recording studio was owned by Sun Records' Sam Phillips, one of those businessmen who were looking for a new type of music that would appeal to teenagers. Something about the truck driver's voice made Phillips think Elvis might be just what everyone had been waiting for.

But who was Elvis, anyway?

Elvis Aron Presley was born in 1935 in a two-room shack in Tupelo, Mississippi. The Presleys were poor, but somehow father Vernon managed to scrape together $7.90 to buy his boy his first guitar, from a local hardware store, when he was 10. (Elvis taught himself to play; the last thing his family could afford was guitar lessons.)

Elvis loved listening to his neighbors make music. He was like a sponge, soaking up all the sounds around him: country songs and gospel songs sung by his white neighbors; spirituals and blues songs sung by his black neighbors. It was his ability to blend all those sounds to create a new and exciting one that would make Elvis different from any other musician.

The First Rock-and-Roll Star

In 1956, four years after the term "rock-and-roll" was invented to describe a new kind of music made mostly by black musicians, "Heartbreak Hotel" became Elvis's first No. 1 rock-and-roll hit.

But not everybody was crazy about Elvis. America was segregated in those pre-civil rights days, and some white radio stations refused to play Elvis's music because they said he sounded like a "Negro." But that didn't slow him down.

Elvis's look was just as important as his music. He had thick black hair, slicked back in a wavy pompadour, and wore really cool clothes. He sneered and swaggered, but with his dreamy eyes and full lips, he was incredibly handsome. Girls wanted to be his girlfriend. And boys? They wanted to be him.

Soon everyone knew who Elvis was, even if they didn't care for his music.

The Beginning of the End

One of the key figures in Elvis's career was his manager, Colonel Tom Parker. He wasn't a real colonel, and in many ways he wasn't much of a manager, either. Parker was always on the lookout for ways to make money off the boy. It was at his urging that Elvis began making movies, most of them embarrassingly bad. Though his popular movies usually featured a handful of songs, Elvis had become more of a movie star than a musician.

He also had become rich. He decorated his Graceland mansion with what seemed like really fancy stuff to a kid born in a two-room shack: lots of mirrors, shag carpet on the ceiling, a television in almost every room. He sometimes rented a Memphis amusement park overnight so he and his friends could have it all to themselves.

But he was often lonely (especially after he and his wife, Priscilla, divorced). He knew lots of people but had few friends he could trust. Performers whose careers he had inspired and influenced -- such as the Beatles -- were becoming more popular than he was.

Being rich and famous, it turned out, didn't equal being happy.

Elvis Leaves the Building

Elvis dealt with his problems by taking drugs. Always a big eater, Elvis also gained a lot of weight. Women (not teenagers anymore) still screamed his name, but it got harder and harder to understand what they were so excited about.

On Aug. 16, 1977, Elvis collapsed in his bathroom, from a heart attack brought on by all the drugs he'd taken. The King of Rock-and-Roll was dead at age 42.

His music, however, lives on.

Elvis Presley was the first rock-and-roll star. He also starred in movies such as "Jailhouse Rock," above.