“These crosses for us were like symbols of hope and liberation,” she said.

During the Stalinist period after World War II, some 300,000 Lithuanians, largely intellectuals, were deported to Siberia; 50,000 never returned. Ms. Kakneviciute first took us to a park dedicated to partisans, or Forest Brothers, young men who waged a guerrilla war against the Red Army despite the threat of certain execution and the deportation of their relatives if caught. “The Hill of Crosses was really developed because lots of people were lost, lots of people were deported,” said Ms. Kakneviciute, “and their families wanted to commemorate them and pray for them to come back from Siberia.”

For decades, the Soviets would clear out the crosses, only for Lithuanians to put them back up again. They gave up clearing in 1970. The last count was around 100,000, but now, Ms. Kakneviciute said, it must be at least 300,000. Nearly everyone who comes to the site leaves a cross anywhere they choose, whether for a loved one’s death or a newborn baby. Even Pope John Paul II made a pilgrimage in the ’90s to leave a giant crucifix. And when a single cross falls over, it leaves a trail of broken crosses, like fallen dominoes.

The Erasure of a People

Among all this, what you may miss, if you’re not looking for it, is the absence of the people who shaped much of the city’s history and cultural life. Before World War II, Lithuania had one of the largest Jewish populations in Europe, dating to the 15th century and topping out at around 250,000. Vilne, as it was called in Yiddish, was one-third Jewish, with over 100 synagogues, and was widely known as the Jerusalem of the North.

Over 90 percent of Lithuania’s Jews were murdered in the Holocaust — the largest percentage of any country in Europe with a substantial Jewish minority. And the executions were not in camps, but by shooting at mass grave sites, largely at the hands of enthusiastic Lithuanian volunteers, including some who would become those lauded Forest Brothers.

You can take a walking tour of the city’s Jewish history and go to the Vilna Gaon State Jewish Museum, both of which I missed because of bad timing. The city’s state-run Museum of Occupations and Freedom Fights (known until April of this year as the Museum of Genocide Victims) is almost exclusively a history of Lithuanians’ oppression at the hands of the K.G.B., the Soviet secret police and intelligence apparatus. The museum’s name had become a huge point of contention for both Jewish visitors and scholars, including Vilnius-based Dovid Katz, who has pointed out many times that the K.G.B.’s horrible acts did not amount to genocide because they were about eliminating dissidents and not exterminating an ethnic minority. Mr. Katz and others still take issue with the museum’s glorification of Lithuanian militants who started killing Jews en masse before the arrival of the Nazis. Nowhere in the city did I see any major memorial to Jewish Holocaust victims.

In Tallinn I had visited its K.G.B. Museum, located in a skyscraper hotel used to spy on foreigners, and found the guide’s jokes about how she wouldn’t confiscate my photos pretty funny. There, Soviet agents and the spy equipment they left when they fled in 1991 are treated like cartoons. Microphones hidden in bread plates! Tiny cameras used in peepholes on picture frames! But when I heard Ms. Kakneviciute talk about the suffering of her grandparents under the K.G.B., those jokes felt grossly shallow.

Every year, she told me, she goes on a “patriotic mission” to Siberia with a group of young Lithuanians to interview any locals who remember the experiences of deportees. They also clean up cemeteries, then come back to tour schools with the stories they’ve learned. “It’s important to remember this still-living history because maybe in 10 years they are all passing away,” she said. “Lots of people are still crying around in Lithuania, ‘Oh, what a bad life we are having!’ But then just think what our grandparents lived through.”