It sits at the base of Montreal's skyline, and it's hard to miss: "Farine Five Roses," it reads in red neon, blinking languorously through the night.

For more than half a century this sign has greeted Montrealers driving over the Champlain Bridge, walking through the Old Port or Little Burgundy, or descending from Mount Royal, but perhaps for not much longer. In July, the sign went dark, its owners having decided to do away with it. As one of Montreal's most distinctive and beloved landmarks faces extinction, a question is raised: do we care enough-or even know enough-about our sign heritage?

The Farine Five Roses sign can be found atop the Ogilvie Flour Mill, a sombre brick edifice that is somehow always bathed in diffuse, grey light. With its clear, straightforward design, it's a deceptively simple signal light, for it belies a history that mirrors that of Montreal. Erected in 1948, it originally read "Farine Ogilvie Flour," named after the wealthy Scots-Canadian family that owned the mill. In 1954, the family name was replaced by Five Roses, a new brand of flour that quickly became a fixture in Canadian households. The next change came in 1977 when, in accordance with Bill 101 (which required all commercial signage in Quebec to be in French only) the last five letters of the sign were removed. Finally, in 1993, the Ogilvie's business was bought by Archer Daniels Midland Company (ADM), an international conglomerate based in Illinois.

"It's a repository for any number of stories," says Matt Soar, a professor of communications at Concordia University who helped create Logo Cities, a project that examines high-rise signs and logos. Farine Five Roses recalls the glory years of neon, he explains, when the ability to make signs blink and simulate movement gave cities a shock of excitement and allure. It tells us about how Montreal grew-the sign's positioning makes it visible from large parts of the city-and how industry shaped that growth. Its transformation from Ogilvie to Five Roses marked the birth of branding. It has a lot to say about language politics: bilingual when most downtown signs and advertisements were in English, unilingual when bilingualism was officially declared to be a threat to French in Montreal. (Even then, where does bilingualism begin and end? "Flour" was removed but the trademarked "Five Roses" remained, a testament to the linguistic contradictions of modern Montreal.) More recently, it tells the story of corporate convergence and globalization, where brands, companies and local landmarks become commodities traded on an international scale.

Earlier this year, ADM sold the Five Roses brand to Smuckers, making the big sign perched atop the old Ogilvie mill irrelevant at best and a liability at worst. To corporate management, then, it seemed only natural to turn the sign off, with the ultimate goal of dismantling it. Big mistake, at least in the eyes of Montrealers. When word came that the sign's days might be numbered, heritage activists and ordinary citizens expressed shock. The Gazette ran an editorial declaring that the Farine Five Roses sign "deserves a place in our hearts, if not our skyline," and urged ADM and Smuckers to keep the sign alive. Soar, for his part, launched a website called Save Farine Five Roses, which contains historical information, an image gallery and an anagram game in which users can rearrange the sign's letters.

After the public outcry, ADM and Smuckers decided to reilluminate the sign until a final decision was made about its future. Many are pessimistic, however. It is unlikely that either company would be willing to invest in the sign's upkeep. The City of Montreal, meanwhile, has shrugged off any responsibility and has refused to acknowledge the sign's heritage value. A spokesman for Montreal's downtown borough pointed out that such a sign would be illegal today because of new bylaws designed to protect views of Mount Royal. But Dinu Bumbaru, the head of the advocacy group Heritage Montreal, insists that the sign's future is of urgent public concern. "It's really not an insult to its surroundings; it's part of the genus of the place that is dedicated to industry, flour milling and trading and so on," he says. "Like the [Guaranteed Pure Milk] bottle, or how people are lining up for Schwartz's smoked meet, [the Farine Five Roses sign] is part of the heritage of the city. It's not a nostalgic thing because it's not part of the past; it's part of today's heritage-the living heritage."

Part of the Farine Five Roses sign's appeal is its sheer presence. It adds visual complexity to Montreal's skyline, creating a natural point of interest to which the eye is drawn. Most charmingly, it is ever so slightly whimsical, working with the mountain's neon cross, Place Ville Marie's rotating spotlight, the illuminated harbour clock and the blue-and-white animation of the Molson brewery sign to create a nocturnal fantasyland of light and colour. "These are the elements of the nightscape," explains Bumbaru, the quixotic collection of things that make the night so much more mysterious and romantic than the day.

Signs are an integral part of both the nightscape and the dayscape. They are part of Montreal's collective heritage, emblems of this city's culture past and present. Yet they are often poorly understood and marginalized; buildings are restored and monuments are protected, yet historically or culturally significant signs rarely fare so well. Farine Five Roses is but one of hundreds of vintage signs in Montreal. Many of these are neon signs from the 1940s and 1950s and handpainted advertisements from even earlier eras. The former are often in disrepair. The latter, faded with age, are known as "ghost ads" for their habit of showing up in unexpected places; disappearing and reappearing with sun, shadow and rain.

The biggest threat to many of these signs is simple negligence. Since they exist on private property and promote businesses that have long since disappeared, civic officials are reluctant to acknowledge their value. Yet they are often beautiful, or at least striking in their design. "There was a lot of craftsmanship that went into them," notes Bumbaru. Their importance extends beyond aesthetics: they are also important reflections of the everyday social and economic life of years past, part of what Bumbaru calls the "archaeology of cities." Sainte-Catherine Street in downtown Montreal is littered with ghost ads. Some advertise pianos, others boots. Ghost ads in the west of Montreal are in English; those in the east are in French. Last year, on the Main, the demolition of several vacant buildings revealed a century-old Lea & Perrins' ad that advised passers-by to "Look out for imitations!"

There are many obstacles to saving old signs. The profusion of cheap, mass-produced backlit signs in the 1970s created a backlash against signage that can still be felt. When old buildings are restored, ghost ads are sometimes erased; many old neon signs are simply discarded, as was the case for the classic sign that adorned the Sainte-Catherine Street entrance to Saint-James' United Church until its restoration this year. Sometimes, politics interfere. In 2005, the owners of the Monkland Tavern in Montreal's West End won a civic award for the restoration of their bilingual 1950s-era neon sign. The ensuing media attention, however, prompted an anonymous militant to file a complaint with the Office québécois de la langue française: the sign's English "tavern" was the same size as the French "taverne," which contravenes Quebec's language laws. The bar was forced to alter the vintage sign at great expense.

If anything, though, such controversy underlines the cultural importance of old signs. Matt Soar points out the unusual step ADM and Smuckers took in re-illuminating the Farine Five Roses sign. "It's culturally relevant to a lot of people," he says. It has become both a temporal and a spatial landmark in many Montrealers' lives, like a childhood home or an old school. Signs like this, worn by time and weather but always very visible, remind us of the city that was and the city that exists today. In these signs, we see ourselves.