Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory in Flagstaff. Here's how Pluto won - and lost - its planetary status.

Visitors to Lowell Observatory follow a path of descriptive signs and busts, named the Pluto Walk, leading to the room where Clyde Tombaugh spent hours peering into the heavens.

Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory in Flagstaff. Here's how Pluto won - and lost - its planetary status.

On the 95th anniversary of its discovery, Pluto remains one of the most beloved and enigmatic worlds in our solar system, whether you call it a planet or not.

Nestled atop Mars Hill in Flagstaff, Lowell Observatory has been a cornerstone of astronomical discovery since 1894 — and it’s still inspiring curiosity today.

Adam Nimoy, the only son of "Star Trek" legend Leonard Nimoy, is one of the keynote speakers at the annual I Heart Pluto Festival in Flagstaff.

When was Pluto discovered? Pluto was discovered in 1930 by Clyde Tombaugh, an American astronomer at the Lowell Observatory in Flagstaff. Cold, dark and distant, it was named after the Roman god ...

Arizona has declared Pluto as its “official state planet” — despite it being relegated to “dwarf planet” status nearly two decades ago.

Arizona Gov. Katie Hobbs signed a bill making Pluto the official state planet. It was discovered at an observatory in Arizona, but was downgraded to a dwarf planet in 2006.

Despite its downgrade in 2006, Pluto, which was discovered in Flagstaff, Arizona, may soon regain its planetary status — at least in the minds of the Arizona Legislature.

To mark the occasion, The Lowell Observatory in Flagstaff, Arizona, where Pluto was discovered, is hosting its sixth annual "I Heart Pluto" festival. But should they? Is Pluto even a planet?

The astronomers at Lowell Observatory in Arizona are showing Pluto some love on the 95th anniversary of its discovery, regardless of whether we call it a planet or not.