in 1989 ktvu's george watson gave us this view as the military prepared to withdraw from the base and hand it over to the national park service. >> reporter: most of the big military projects in the bay area began in the 1950s and they did not include the precidio itself. four point was to be the main base of defense against the confederate south which was thought to be on the way of seizing california. that was the thinking in 1861. four point was reassuring and at the same time impressive. but alcatraz was designed to throw fear. it was thought to be inpregnable. it was in fact, the war like san francisco bay. during the civil war years, 1861 to 1865, alcatraz bristles with 804 cannons. most of the cannons were along this side of the island. they faced the city of san francisco but more importantly, they faced the mouth of the golden gate. from here, alcatraz was the strong point of something known then as the triangle of death. at one leg of the triangle layed four point, guarding the entrance to the bay. alcatraz with its 105 guns was the center point for symmetrical reasons. any

here's ktvu's george watson with a look back at the tet offensive and san francisco that same year. >> in 1968 it became painfully obvious that vietnam was not a war we were going to win. the whole affair seemed in couch cover up phrases like the odd of the fire. it was a war like no other yet like every other war. young men fighting, leading and dying. yet vietnam was vastly different in another respect. it came home every night on the 6:00 news. man's inhumanity to man. constant and up close and personal. cong led the tet offensive blitzing. >> the biggest fact is the states purposes of the general uprising a military victory or psychological victory have failed. >> reporter: two months later vietnam claimed america's highest office. lyndon johnson was going away. he had not won and would not win. >> i shall not seek and will not accept the nomination from my party for another term as president. >> reporter: just a fraction of the carnage that was yet to come. yet america's military leaders still insisted they were in control and that the war was going well. fanning the flames of pr