Living in Kinshasa in the mid-1990s, I often drove past a futuristic tower looking out over the slow-moving, hyacinth-spotted river separating what was then Zaire from its neighbor, Congo-Brazzaville. The tower was a medley of gleaming metal tubes and concrete pillars, and its raison d’être was a bit of a mystery: It wasn’t particularly beautiful, had been left unfinished for decades, and couldn’t be visited. That ambiguity was fitting. The Limete Tower, as it was called, was an exercise in presidential hypocrisy, and a half-hearted one at that. Mobutu Sese Seko, Zaire’s long-ruling dictator, had commissioned it to commemorate his former boss and onetime friend Patrice Lumumba, the first prime minister of independent Congo. Lumumba was assassinated in January 1961 with the collusion of Western powers worried about his suspected Communist sympathies and determined to keep him from power. In theory, the monument was meant to glorify a national hero, a martyr to imperialism. But the gesture’s sincerity was open to question, because Mobutu himself helped ensure Lumumba’s death, ordering him to be flown handcuffed …