The rainbow flag stands out as this era’s best-known LGBT symbol. From San Francisco’s Castro to Chicago’s Halsted Street to New York City’s Greenwich Village, the flag is widely flown—during June and throughout the year—to celebrate gay pride.

The rainbow has been used by many cultures, including indigenous peoples of the Americas, as a symbol of hope. But the use of the rainbow flag to symbolize gay pride originated with artist Gilbert Baker, dubbed the "Gay Betsy Ross," in 1978.

Baker grew up in Kansas as an effeminate child with an interest in fashion. In high school, he reportedly created a pop-art flower dress for his date to wear to the prom. Baker arrived in San Francisco in 1970 as a draftee stationed at the Presidio army base, where he worked as a nurse. He began taking acid, joined the drag revolution pioneered by the Cockettes and the Angels of Light, and eventually received an honorable discharge. "One taste of Sylvester and I couldn’t wait to trade medical whites for gold lame and a feather boa," he later recalled.

According to Baker, "Gay life in the new generation was about being in your face, out of the closet, not waiting for power but taking it." He often stayed up nights making banners for political protests, and he organized volunteers to create decorations for the city’s annual Gay Pride celebration. The idea for the rainbow flag was hatched when Baker’s friend, Harvey Milk, an openly gay candidate for the Board of Supervisors, suggested the movement needed a symbol other than the pink triangle, which had originated in Nazi Germany as a badge of oppression.

With a group of friends, Baker hand-dyed and stitched the first two rainbow flags at the local gay community center. The original version consisted of eight horizontal stripes in fuchsia, red, orange, yellow, green, turquoise, indigo, and violet, representing sex, life, healing, sunlight, nature, art or magic, harmony, and spirit, respectively.

The flags made their debut at the June 1978 San Francisco Gay Freedom Day parade. "When we raised the flags on large poles in United Nations Plaza the morning of the parade, we knew we’d created something magical," Baker recalled. "It was the most thrilling moment of my life." The flag took on greater political significance when a seven-color version—Baker could not find fuchsia fabric in time—was carried in a candlelight march following Milk’s assassination in November 1978.

Baker approached the Paramount Flag Company about manufacturing the flag, but his original hand-dyed colors were not all commercially available. Thus, fuchsia and turquoise were omitted, and royal blue was substituted for indigo.

Without any concerted effort at publicity or marketing, the six-color rainbow design was widely adopted, flying in front of homes and businesses, adorning car bumpers, and appearing on T-shirts, key chains, and jewelry. Since flags cannot be copyrighted and the design remained in the public domain, Baker never profited from the explosion of rainbow-hued paraphernalia.

While the rainbow flag is said to represent LGBT diversity, specific queer communities have adopted their own flags. At the May 1989 International Mr. Leather contest, Tony DeBlase introduced a Leather Pride flag comprised of four black and four blue horizontal stripes, a white stripe in the middle, and a red heart in the upper left corner. An early bear flag with diagonal stripes was supplanted by the International Bear Brotherhood flag, designed by Craig Byrnes in 1995, which features horizontal stripes in the fur colors of bears throughout the world and a paw print in the upper left corner. The Bi Pride flag, created by Michael Page, debuted in 1998. Comprised of pink, purple, and blue horizontal stripes, it evolved from a symbol created by Liz Nania featuring pink and light blue triangles overlapping to form lavender.

For the 25th anniversary of the Stonewall Riots in 1994, Baker created a 7,000-pound, mile-long rainbow flag that was carried by 10,000 people through the streets of New York City. Spectators along the parade route threw money into the flag, raising $40,000 for a food program for people with AIDS.

By the rainbow flag’s 25th anniversary, it had become possible to commercially manufacture a wider variety of colors, and Baker reintroduced fuchsia and turquoise. "[W]hen we lost the pink, we lost the symbol for sexual liberation. The missing turquoise honors Native Americans and the magic of life," Baker said. "Both colors are needed to embrace our history." To celebrate the anniversary, Baker supervised a team of hundreds to create a 1.25-mile-long banner in the original eight colors that was unfurled across the island of Key West from the Atlantic Ocean to the Gulf of Mexico during that city’s June 2003 Pride celebration.

"Flying the flag is a visibility action, whether it is a discreet sticker on a car windshield or ten stories high," said Baker. "Even the often tacky commercialization...pushes our message to the farthest reaches of the earth."