HONG KONG - THIRTY years ago I was fortunate enough to take a photograph that has become perhaps the most recognizable image of the fall of Saigon -- you know it, the one that is always described as showing an American helicopter evacuating people from the roof of the United States Embassy. Well, like so many things about the Vietnam War, it's not exactly what it seems. In fact, the photo is not of the embassy at all; the helicopter was actually on the roof of an apartment building in downtown Saigon where senior Central Intelligence Agency employees were housed.

It was Tuesday, April 29, 1975. Rumors about the final evacuation of Saigon had been rife for weeks, with thousands of people -- American civilians, Vietnamese citizens and third-country nationals -- being loaded on transport planes at Tan Son Nhut air base, to be flown to United States bases on Guam, Okinawa and elsewhere. Everybody knew that the city was surrounded by the North Vietnamese, and that it was only a matter of time before they would take it. Around 11 a.m. the call came from Brian Ellis, the bureau chief of CBS News, who was in charge of coordinating the evacuation of the foreign press corps. It was on!

The assembly point was on Gia Long Street, opposite the Grall Hospital, where buses would pick up those wanting to leave. The evacuation was supposed to have been announced by a "secret" code on Armed Forces Radio: the comment that "the temperature is 105 degrees and rising," followed by eight bars of "White Christmas." Don't even ask what idiot dreamed this up. There were no secrets in Saigon in those days, and every Vietnamese and his dog knew the code. In the end, I think, they scrapped the idea. I certainly have no recollection of hearing it.

The journalists who had decided to leave went to the assembly point, each carrying only a small carry-on bag, as instructed. But the Vietnamese seeing this exodus were quick to figure out what was happening, and dozens showed up to try to board the buses. It took quite a while for the vehicles to show -- they were being driven by fully armed marines, who were not very familiar with Saigon streets -- and then some scuffles broke out, as the marines had been told to let only the press on board. We did manage to sneak in some Vietnamese civilians, and the buses headed for the airport.

I wasn't on them. I had decided, along with several colleagues at United Press International, to stay as long as possible. As a Dutch citizen, I was probably taking less of a risk than the others. They included our bureau chief, Al Dawson; Paul Vogle, a terrific reporter who spoke fluent Vietnamese; Leon Daniel, an affable Southerner; and a freelancer working for U.P.I. named Chad Huntley. I was the only photographer left, but luckily we had a bunch of Vietnamese stringers, who kept bringing in pictures from all over the city. These guys were remarkable. They had turned down all offers to be evacuated and decided to see the end of the war that had overturned their lives.

On the way back from the evacuation point, where I had gotten some great shots of a marine confronting a Vietnamese mother and her little boy, I photographed many panicking Vietnamese in the streets burning papers that could identify them as having had ties to the United States. South Vietnamese soldiers were discarding their uniforms and weapons along the streets leading to the Saigon River, where they hoped to get on boats to the coast. I saw a group of young boys, barely in their teens, picking up M-16's abandoned on Tu Do Street. It's amazing I didn't see any accidental shootings.