The best and worst of nationalism run through the Olympics. The worst is easy: Berlin 1936, Munich 1972. The best is harder to pin, but it is based on pride in where you come from—including your culture's diversity and human rights. The U.S. team, for example, is as diverse as any Olympic team in history, and this is the first time its women outnumber its men. We can be proud of that because it pushes change.

"These are transitional Olympics and could be transformative ones," says Craig Neff, who has run SI's Olympic coverage since 2000 and has covered 11 Games. "We see the last of great stars like Michael Phelps and the last—for a while at least—of traditional Western host cities. From here the Games go to Sochi, Rio and Pyeongchang, and maybe Istanbul in 2020. For the IOC to venture into the new Russia, South America and possibly the Muslim world signals as big a global shift as the 2008 Olympics going to Beijing."

The first revolutionary moment of the London Games will come when women athletes from Brunei, Qatar and Saudi Arabia march into the Olympic Stadium during the opening ceremony. Qatari shooter Bahiya al-Hamad, 19, will carry her country's flag. None of those countries has sent a female athlete to the Games before. Even if this handful of women (one Bruneian, two Saudis, four Qataris) is largely symbolic, the power of Olympic symbolism resonates. A billion people around the world are watching.

Many of the athletes competing in London define courage in their homelands. The fastest sprinter in Egypt's history, Amr Seoud, was among the first wave of protesters to arrive at Tahrir Square in Cairo on the morning of Jan. 25, 2011, to denounce police abuses and three decades of "emergency" laws that had allowed indefinite detention without trial during Hosni Mubarak's 29-year dictatorship. A month earlier in Tunisia, 26-year-old fruit vendor Mohamed Bouazizi had set himself on fire after being harassed by police, the catalyst for what quickly became known as the Arab Spring. The uprisings that swept across North Africa and the Middle East did not signal the triumph of democracy, but they placed a halo on those willing to die for it. The realpolitik of revolution may have been debated on television, but on the ground with Seoud, revolution was real and could easily end in jail or worse. Three days after the Tahrir uprising, bullets fired from a passing ambulance killed a neighbor Seoud was talking to. In Yemen, judo champion Ali Khousrof tried to hide his participation in antigovernment sit-ins from coaches, but that became impossible after he was hit by shrapnel during a march. Ezzideen Tlish, a two-time Libyan taekwondo Olympian headed for London, was killed while working with rebel medics. There are many stories (Arab Spring, page 100). They are all important.