The Welcome to Las Vegas sign at the south end of Las Vegas Boulevard greets visitors to Sin City.

Reaching the Big Five-O isn't easy for Vegas landmarks. One day you're hot, the next day you're history. But the city's iconic Welcome to Fabulous Las Vegas sign, which turns 50 this year, shines just as brightly as it did when Ford Fairlanes plied old U.S. Route 91 from Los Angeles. "I always called it ‘the little sign that could'—and it did," says Betty Willis, 85, who created the classic emblem. Topped by a neon starburst and rimmed by gold chasing lights, this beacon to fun seekers stands on a grassy median at the south end of Las Vegas Boulevard. Willis's playful design continues to adorn kitschy keepsakes from ashtrays to shot glasses. visitlasvegas.com.

The 70-foot-tall Willits Arch in tiny Willits, Calif., began life in 1964 welcoming visitors to Reno. It now spans Highway 101, proclaiming Gateway to the Redwoods and Heart of Mendocino County on opposite sides. willits.org.

Besides the Space Needle and Mount Rainier, few landmarks say Seattle like Pike Place Market's 1920s red neon sign. Benefactors bid each year for the right to scale hidden stairs and reset its dinner-plate clock. pikeplacemarket.org.