Walking through the heart of San Francisco's Mission District often feels like stepping out of the U.S. and into a bustling Central or South American city. The neighborhood's vibrant street life, a medley of packed sidewalks, bright colors, and the smell of freshly cooked food, attracts residents and tourists year round. But yesterday, the Mission felt more like a ghost town.

Rows of shuttered businesses, closed in solidarity with the country-wide May 1 protests held to demand equal rights for immigrants, gave a harsh welcome to anyone venturing into the district's relatively deserted streets yesterday. Those restaurants and shops that chose to stay open did so at their own peril, telling anyone who asked that business had been terrible due to the rallies.

Protests held across the country yesterday varied in size and scope, with events ranging from massive work and school walk-outs to small lunch hour press conferences on the steps of the local City Hall.

The message was unified one, though - this is what a day without immigrants would look like. As lawmakers in Washington decide the fate of millions of people living in the United States who came from elsewhere, activists attempted to reframe the debate from what immigrants cost America to what the country receives from immigrants.

It's doubtful that this message was made more forcefully anywhere else than in San Francisco's Mission District.

Home to the majority of the city's Latino population, the Mission hosts a variety of immigrant-owned businesses. Ranging from clothing shops to taquerias, these businesses often serve both as gathering places for those new to the country as well as a place to purchase goods.

Yesterday, however, virtually every Latino owned business shuttered its doors. A host of unique signs explained in different ways the reasons for the closure, ranging from the complex and political ("Immigrant Solidarity - The Great American Boycott 2006") to the simple and heartfelt ("We Are Supporting Our Families").

Walking down Mission Street felt almost like walking through a prison, with rows and rows of vertical metal bars constantly in peripheral vision. For many of the business's owners, however, the symbolism could become real, with a new law still being debated on Capitol Hill that would make illegal immigrants and those that helped them into felons.

Yesterday, however, the bars represented a different kind of prison - one that didn't lock immigrants out, but instead locked out the economic benefit non-immigrant Americans reap due to Latino presence in the U.S.

"Business hasn't been normal at all today. Not even close," said Nick, the manager of New Colors Fashion, a clothing store on 16th and Mission, who preferred not to give his last name. "It's been much slower. People just aren't coming in."

"Has it affected our business in terms of sales? Definitely," said Ronald Otero, a retail clerk at a T-Mobile store on 17th and Valencia. "We've seen a difference, for sure."

While they were often hard to find, those that did stay open for business had an almost universal response when asked how business was yesterday - bad. Really bad.

By effectively shutting down the economy in one of the densest and most tourist-friendly neighborhoods in a major American city, immigrants made a profound point in San Francisco yesterday.

A day without immigrants means a day without a substantial portion of the workforce. It means a day without a massive chunk of consumers, who work hard to earn money that they then spend in the U.S. And it means the death of some of the country's most vibrant communities. In San Francisco, a day without immigrants meant a day without the Mission.