The first television drama aired in 1928, but it wasn't until after World War II that TV really took off. Today, satellite and cable options provide a TV smorgasbord. Although many news programs and soap operas have lasted longer, we've narrowed this list down to longest-running dramas and sitcoms in United States­ television history. Grab the remote and take a trip down TV's memory lane.

1. Gunsmoke (1955-1975)

Gunsmoke tops the list as the longest-running dramatic series in network television history with 635 episodes. Set in Dodge City, Kansas, during the 1870s, Gunsmoke began as a radio program in 1952, switched to the land of visual entertainment in 1955, and finally ended its 20-year run in 1975.

State Archive of Florida Lassie entertained audiences for over 18 years.

2. Lassie (1954-1972)
Running for 588 episodes, Lassie centered around a loyal canine companion who rescued her human family from various predicaments. Over the years, Lassie was portrayed by nine different male dogs, all descendants of the original Lassie, whose real name was Pal. During the show's run, Lassie had various owners, most notably Timmy and Jeff. Only three dogs have a star on the Hollywood Walk of Fame -- Lassie, Rin Tin Tin, and Strongheart.

3. Death Valley Days (1952-1970)

In 1952, Death Valley Days, which aired as
a radio show from 1930 to 1945, evolved into a successful TV show that lasted 18 seasons. A host introduced each of the 451 episodes, which were based on actual pioneer stories that took place in southeastern California and western Nevada during the late 1800s. Future President Ronald Reagan and country singer Merle Haggard were among the hosts during the show's run.

4. The Adventures of Ozzie and Harriet (1952-1966)

What began as a radio program in 1944 became a movie (Here Come the Nelsons) in 1952 and then a successful television program that ran for 435 episodes. In this wholesome show, the characters played themselves -- Ozzie and Harriet Nelson and their two sons, David and Ricky. Ozzie's roots were in music, so when Ricky's talent started to emerge, Ozzie wrote it into the story line, ending each show with a performance by his younger son. These weekly, televised performances helped skyrocket Ricky onto the pop charts, making him a teen idol as well as a successful recording artist.

Our list of the 10 longest-running TV shows continues on the next page.

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