OSWIECIM, Poland — President Bush passed under Auschwitz gate's chillingly misleading proclamation that "work makes you free" to pay tearful tribute Saturday to the victims of Nazi death camps. "Never forget," he exhorted.

Bush and his wife, Laura, spent nearly two hours touring the Auschwitz and Birkenau extermination camps, the president calling them "a monument to the darkest impulses of man."

The Bushes saw long-abandoned baby shoes, Jewish prayer shawls, battered suitcases, artificial limbs and other items that belonged to those who passed through Auschwitz's gate not to earn their freedom but to die.

They saw masses of hair shorn from victims for shipment to German textile makers, who would weave it into clothing.

They saw the tiny cell once inhabited by Nobel Prize laureate Elie Wiesel in his boyhood.

They read a sign that said, in German, "Jews are a race that must be totally exterminated."

Bush periodically wiped tears from his eyes, exhaling deeply at one point as if to compose himself and later pulling out a handkerchief as he and the first lady walked through the complex. The crunching of gravel underfoot and the quiet narration of their tour guide were almost the only sounds.

More than 1.5 million Jews and tens of thousands of others were killed at Auschwitz and Birkenau, about 50 miles west of Krakow, where Bush delivered a speech on U.S.-European relations and the war on terrorism.

At Auschwitz, now a museum, the Bushes walked through the interior of a gas chamber.

They helped lay wreaths at both camps— against a brick wall at Auschwitz marking a site where prisoners were once lined up and shot, and where the railroad tracks into Birkenau abruptly end. It was literally the end of the line for trainload upon trainload of victims of the Third Reich.

On either side of the railhead were the remains of crematoriums blown up by the Germans as they fled the camps ahead of advancing allied armies.

Looking at the rubble in bright sunshine, Bush told reporters: "The sites are a sobering reminder of the power of evil and the need for people to resist evil."

Bush's tour of the camps was designed to underscore his oft-repeated message that evil never again should be left unchecked. But the president seemed shaken, and his observations were mostly terse: "powerful," "so sad," "all the little baby shoes."

In a guest book, Bush's words had already been written in flowing script: "Thank you sincerely for a deeply moving tour, and dedicating your lives to preserving the memory of the Holocaust and the martyrdom of Poles. You honor all who are victims here. May your work inspire future generations to stand ever vigilant against the return of such unspeakable evil to our world."

To that he added, "Never forget" in his own handwriting and signed his name.

Later, in a speech at Krakow's Wawel Royal Castle square, Bush told his audience he had visited "a place where evil found its willing servants and its innocent victims."

Bush quoted Wiesel, recalling on a return visit many years after his first night in the camp: "I asked myself, God, is this the end of your people, the end of mankind, the end of the world?"

Said Bush: "With every murder a world was ended."