Day 0: In Tucson … for now (July 17, 2006) Tomorrow we leave for San Diego/Tijuana. 21 Days on the border – hard to fathom. That will be longer than an entire Olympics; Mardi Gras (well, the tourists' version, anyway); a fortnight; the Lord of the Rings trilogy, viewed 50 times in succession; your 5-year-old niece's rendition of the Nutcracker, viewed just once; ... well, you get the picture. Our journey will take us from Tijuana to Brownsville, via Tecate, CA and MX, Yuma, AZ, Sasabe, MX, Columbus, NM, Ciudad Juarez, MX, Big Bend, TX, Del Rio, TX, Nuevo Laredo,...