As thousands of people descend upon Harvard Yard today, expect tight security enforced by the U.S. Secret Service, the South African Secret Service and the local police.

All this week, officers from the special operations branch of the Harvard University Police Department (HUPD) have assisted the U.S. Secret Service and other agencies in laying a heavy security blanket.

"There will be security in place, but we won't go into specifics," said John Rodriguez, the Secret Service special agent handling advance preparations.

Although both the old and new Yards will be open today, Tercentenary Theater, the area in the New Yard between Widener Library and Memorial Church, will be closed, according to Francis H. "Bud" Riley, the chief of the HUPD.

As for the outside perimeter of the theater, "it looks like basically, some kind of snow-type fencing around key areas," said Harvard News Office Director Joe Wrinn.

"There'll be a special section in the front and a small press area in the front," he said.

"Behind that [is for] general admittance tickets," he said.

Beginning at noon Friday, the snow fencing will be erected around Tercentenary Theater, around Canaday, Thayer, University, and Weld halls on the west side, and from Widener Library to Sever Hall on the east side, Wrinn said.

Access will be restricted after 12 p.m., although Wrinn said students should have no problems getting to their classes.

From 12 p.m. to 3 p.m. today, organizers will make last-minute preparations and security officers will sweep the Yard for anything out of the ordinary.

Students and visitors will be allowed into the theater beginning at 3 p.m.

The event is open to Harvard students with I.D.'s, and members of the general public were able to request tickets through the University.

Wrinn said he expects between 7,700 and 8,000 people to attend the ceremony. All 5,000 tickets available to the public have already been distributed.

A special request from Mandela for all who attend: Don't use flash photography. Mandela's years in prison left him with a medical condition affecting his eyes.

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