Only the most determined tourist could avoid San Francisco's Market Street.
As this video shows, it begins at the Ferry Building on the Embarcadero. At Powell Street near Union Square, it includes one of the city's busiest cable car turnarounds. It continues through the long-bedraggled blocks around City Hall to the lively, prosperous Castro District.
For all its utility, Market Street has also been a sore point for years -- a refuge for lost souls and sketchy characters. Many blocks are still dodgy to walk after dark, but the street is evolving.
As this video shows, Twitter headquarters, at Market and 10th, is part of the change -- it has sprouted a new market and a set of restaurants downstairs. The relocated Levi's flagship store is another new element, as is the Strand, a revived performance venue for the American Conservatory Theater.
So if you visit now, you'll see a street in transition. This video gives you a good glimpse of Market, up and down. And the way things are going, it'll be outdated soon.