college classrooms, and visits to museums and historic places all weekend every weekend on c-span three. the c-span cities tour travels the country exploring the american story. like many americans, our staff is staying close to home. next, a look at one of art city tour visits. lewis: we are standing on the historic part of the san antonio riverwalk, which developed into one of the world's great linear parks. it is not something that started out to be back in the 1700s, when san antonio was established. this was the major source of

water for the residents of the city. there were various irrigation ditches that came from it and furnished water to the growing community. as the city grew, the railroad came in the 1870's and the population exploded. gravity driven water systems were not working. just say could not get water to run over a hill. so a new water system was established with artesian wells. when drilled into the ground, took water from the ground and they lowered the water table. so the san antonio river was frequently going dry. at that point, in 1914, the city created a park through downtown along what was to be the riverwalk. a park and plantings, not too much else. which was here for about 25 years.

with the wpa a project was , initiated to develop the riverwalk. an architect, robert husband, came up with a design that would give a fanciful appearance to the area. it would include shops and boats and colorful walkways that would dress up the rivers. which did all right, except that nobody came down to the riverwalk. it became dangerous. it was not until san antonio's world's fair in 1968, that enough hotels were built on the riverwalk, to generate a strong pedestrian traffic, strong enough to support businesses and all of a sudden there was a lot of commercial development and the riverwalk became successful as we know it. by being below the level of the street, it is warmer down here.

we have essentially a semitropical botanical garden in the plantings along the riverwalk. there are not the cold breeze as you have above. plants thrive that could not thrive at street level. another hallmark of the riverwalk are the cypress trees which are planted along the banks. these have roots that go down and hold the soil. but they also get very tall. and so as the hotels are built along the riverwalk, the cypress es give a sense of scale. they keep the tall buildings from overwhelming the riverwalk itself. so you get a sense of being in a very different environment. the part of the river we are on right now, the riverwalk, is two miles. this was originally a loop that headed east and then south and west again.

and it was connected by a flood control channels so the water would not have to come all the way around. this is the historical part of the riverwalk in the 1930's. about 10 years ago, the riverwalk was expanded to the north, in an area called the museum reach because there are several museums along their and commercialeen development to the north. it was extended south. the length of the riverwalk is now 15 miles. the advantage to the starts and stops we have had along the way is the buildings have evolved and the surroundings have evolved in almost a haphazard way, which does not give the appearance of the place which was suddenly created in one stroke to be what it is it gives . a sense of the passage of time,

-- it is. it gives a sense of the passage of time, and of interest that is much of the charm of the riverwalk. >> you can watch this and other programs on the history of communities at c-span.org/ citytour. tv is windingry back the clock to feature archival films about historic campaigns. assignment >> this fall, american history tv is winding back the clock to feature archival films about historic campaigns. next, "assignment washington, the correspondent marino de medici," profiling an italian newspaper journalist as he goes about his day-to-day activities in washington and covers the 1976 presidential contest between president gerald ford and challenger jimmy carter. ♪ marino: washington is like a marino: washington is like a room with an enormous circular window.