WASHINGTON - As new polls put Rudy Giuliani and Hillary Clinton on a White House collision course, the former First Lady yesterday unveiled an ad that forecasts future attacks on the ex-mayor's handling of 9/11. (See the ad below.)

The spot, touting Clinton's health care creds, doesn't mention Giuliani but slaps at the treatment rescue workers received.

"She stood by Ground Zero workers who sacrificed their health after so many sacrificed their lives," the script says, with a stark photo of Clinton wearing a mask near the wreckage of the twin towers.

Africa is the world's second-largest and second most-populous continent, after Asia. At about 30,221,532 km² (11,668,545 mi²) including adjacent islands, it covers 6% of the Earth's total surface area, and 20.4% of the total land area.[1] With more than 900,000,000 people (as of 2005)[2] in 61 territories, it accounts for about 14% of the world's human population. The continent is surrounded by the Mediterranean Sea to the north, the Suez Canal and the Red Sea to the northeast, the Indian Ocean to the southeast, and the Atlantic Ocean to the west. There are 46 countries including Madagascar, and 53 including all the island groups.