YEREVAN, Armenia — It has been 30 years since the fall of the Berlin Wall. A guard threw open a gate, the Soviet imperium folded, more than 100 million people in Central and Eastern Europe were freed, a divided continent was made whole, and the end of history was announced.

What to make of the three decades after Nov. 9, 1989? Poverty receded. Lives got longer. Human exchange became borderless. Artificial intelligence started making things smart. China rose, as did sea levels. The United States, attacked and wounded, tried managed decline, and at last, in wild frustration, elected a loudmouthed con man to its highest office. History, not terminated after all, ushered in a new wave of nationalism, nativism and xenophobia.

Water is the new oil. Data is the new plutonium. Climate is the new Armageddon. The talk in 1990 of the inevitability of a world of liberal democracy turned to predictions of a world of autocrats buttressed by the surveillance states that technology has enabled. It has proved impossible for technology companies to do no evil.

The best of all possible worlds was deferred yet again. Joachim Gauck, the Lutheran pastor and anti-Communist East German activist who later became president of a united Germany, captured the illusions and shattered hopes of 1989 best: “We dreamed of paradise and woke up in North Rhine-Westphalia.”