CAIRO, Egypt — Tourists have long been awed by Egypt's famed Giza Pyramids and irritated by having to fend off peddlers relentlessly offering camel rides and trinkets.

But the hustlers were gone Monday as Egypt started an elaborate project to modernize the area and make it friendlier to tourists. Security is also improving, with a 12-mile chain-link fence featuring cameras, alarms and motion detectors.

"It was a zoo," said Zahi Hawass, Egypt's chief archaeologist, recalling the past free-for-all. "Now we are protecting both the tourists and the ancient monuments."

The three Giza Pyramids have been unusually open for a 5,000-year-old Wonder of the World.

The desert plateau on which they stand was once isolated. But as the capital has expanded, slums have been built right to the edge of the site, separated in places by only a low stone wall. The rest of the area has been wide open to the desert.

Tourists undergo a constant barrage from peddlers selling souvenir statues, T-shirts and other trinkets. Visitors are sometimes followed by men on camels selling rides or photos — and rarely taking no for an answer.

Young men even try to force their way into taxi cabs carrying foreigners toward the pyramids, looking to steer them to nearby horse stables for a ride around the site.

But tourists have taken their own liberties. Climbing the Pyramid of Khufu, the biggest of the three monuments, was a favorite challenge for visitors beginning in the 19th century and continuing into the 1970s, despite the occasional fatal fall of an inebriated tourist.

Since then, authorities have cracked down on climbing the giant 2.5-ton blocks, though visitors can still ramble freely around the pyramid grounds, where many tombs and other archaeological sites remain only partially excavated and vulnerable to damage.

Security concerns were highlighted in 1997, when Islamic militant gunmen attacked tourists at a desert temple in the southern city of Luxor, killing more than 60. Most attacks ended in the late 1990s, but bombings in Sinai beach resorts in the past four years have kept officials wary.

The new technology aims to curb shenanigans by both tourists and peddlers.