<P> The River Walk is a successful special - case pedestrian street, one level down from the automobile street . The River Walk winds and loops under bridges as two parallel sidewalks lined with restaurants and shops, connecting the major tourist draws from the Shops at Rivercenter, to the Arneson River Theatre, to Marriage Island, to La Villita, to HemisFair Park, to the Tower Life Building, to the San Antonio Museum of Art, to the Pearl and the city's five Spanish colonial missions, which have been named a World Heritage Site, including the Alamo . During the annual springtime Fiesta San Antonio, the River Parade features flowery floats that float down the river . </P> <P> In September 1921, a disastrous flood along the San Antonio River took 50 lives . Plans were then developed for flood control of the river . Among the plans was to build an upstream dam (Olmos Dam) and bypass a prominent bend of the river in the Downtown area (between present day Houston Street and Villita Parkway), then to pave over the bend, and create a storm sewer . </P> <P> Work began on the Olmos Dam and bypass channel in 1926; however, the San Antonio Conservation Society successfully protested the paved sewer option . No major plans came into play until 1929, when San Antonio native and architect Robert Hugman submitted his plans for what would become the River Walk . Although many have been involved in development of the site, the leadership of former mayor Jack White was instrumental in passage of a bond issue that raised funds to empower the 1938 "San Antonio River Beautification Project", which began the evolution of the site into the present 2.5 - mile - long (4 km) River Walk . </P> <P> Hugman endorsed the bypass channel idea (which would be completed later that year) but, instead of paving over the bend, Hugman suggested 1) a flood gate at the northern (upstream) end of the bend; 2) a small dam at the southern (downstream) end of the bend; and 3) a Tainter gate in the channel to regulate flow . The bend would then be surrounded by commercial development, which he titled "The Shops of Aragon and Romula". Hugman went as far as to maintain his architect's office along the bend . </P>

What is the length of the riverwalk in san antonio