(CNN) — More than seven decades after the U.S. military dropped an atomic bomb on the Japanese city of Hiroshima, effectively ending World War II, the site of the devastation remains one of the most popular tourist attractions in the country.
And it appears to be getting more popular.
Visits by foreign tourists to the Hiroshima Peace Memorial Museum hit a record high of 338,891 in 2015. That's more than a 100% increase from just four years ago.
Visitors to Japan come to bear witness to preserved burnt wreckage, painful survivor testimonies and human shadows left permanently visible after the atomic bomb explosion's incandescent destruction.
A number of factors lay behind the site's continuing hold on travelers.
Some describe Hiroshima as a gripping, educational and emotional example of "dark tourism," "grief tourism" or "battlefield tourism," which includes Nazi concentration camps in Europe, Cambodia's torture prison and killing fields, and West African slave ports, as well as the Nagasaki Peace Park and Atomic Bomb Museum.
The latter site memorializes the events and devastation surrounding the second atomic bomb dropped on that Japanese city three days after the Hiroshima bombing.
The now-iconic structure, designed in 1915 by a Czech architect, was the city's Industrial Promotion Hall. When the United States dropped the bomb on August 6, 1945, it exploded just above the building, but didn't totally destroy it because the immediate blast and heat buffered the air at ground zero.
Hiroshima's Atomic Bomb Genbaku Dome became a UNESCO World Heritage Site in 1996. When the United States dropped the atomic bomb on August 6, 1945, it exploded just above the building.
In addition to the Peace Memorial Museum, Hiroshima officials are actively promoting the city's peace-centric identity.
In 2015, Hiroshima Mayor Kazumi Matsui launched a series of projects around the park. Exhibition rooms in the museum's East Building, for example, were scheduled to be closed for renovations until October 2016. The Main Building remains open.
The city's various projects, estimated to cost roughly 107 million yen (about $861 million), focus on preserving the memories of the bomb's survivors and enhancing the city's ability to attract and accommodate tourists.
Projects include renovations to the Cenotaph for the A-bomb Victims that stands at the heart of the Hiroshima Peace Memorial Park, and renovations to the Rest House, one of the few buildings that survived the blast.
TripAdvisor calls Peace Memorial a top Japan attraction
Even without the new projects, Hiroshima is one of the most well-known destinations in Japan. Americans comprise the largest number of foreign visitors, followed by Australians and Chinese, according to local government statistics for the city and surrounding prefecture.
Countless Japanese also visit.
"The name 'Hiroshima' has been well-known among foreign countries from its history, and recently word-of-mouth effect from visitors adds more reality to it," Hiroshima Convention and Visitors Bureau representative Taeko Abe told CNN. "In recent years, word-of-mouth information from the Internet also has a strong influence."
TripAdvisor currently lists Hiroshima as the country's No. 2 attraction, behind Miyajima island, also located in Hiroshima prefecture.
School bag with wooden grip: student Mitsuko Kawamura (then 13) was exposed to the bomb. Her sister Yaeko searched the city but found only her bag.
Toshio Kawamura/Hiroshima Peace Memorial Museum
The atomic bomb was dropped over Hiroshima from an American B-29 bomber. The explosion obliterated nearly everything within 10-square kilometers (six square miles) in the downtown area, killing 60,000 to 80,000 people. Radiation poisoning eventually sickened others, resulting in an estimated final total death toll of 135,000 people.
Across the Motoyasu River, which flows in front of the A-Bomb Dome, the Hiroshima Peace Memorial Museum displays evocative exhibits, including a blistered and fused tricycle that a four-year-old boy was riding during the blast that burned him to death.
Photos, documentary films, nightmarish drawings by survivors, scientific explanations of the explosion, plus other artifacts, including melted glass and charred clothing, hint at the unimaginable.
"This museum was established by the city of Hiroshima to convey the reality of the atomic bombing to the world, and contribute to the total abolition of nuclear weapons, and realization of lasting world peace," Hiroshima Peace Memorial Museum director Kenji Shiga has told CNN.
Why so many visit
This clock, displayed at Hiroshima Peace Memorial Museum, stopped at the time the world's first atomic bomb hit Hiroshima,
Junko Kimura/Getty Images AsiaPac/Getty Images
"Hiroshima City has achieved a remarkable recovery" since the atomic bomb was dropped, said Abe of the Hiroshima Convention and Visitors Bureau.
"Visitors say they feel its most powerful message, that of hope, and appreciate anew the importance of peace," he said.
"The impression of Hiroshima that visitors take away seems to be affected by whether they have had the opportunity to meet and communicate with local people," Abe said.
Peter Kuznick, director of the Nuclear Studies Institute at American University, has been taking students to Hiroshima for two decades.
"To be in the moment there, especially after you've studied it so much, is very powerful. It's different than just reading about it or learning about it," he said.
Working with his colleague, Koko Tanimoto Kondo, an A-Bomb survivor, Kuznick began bringing Japanese and American students together each summer to travel to Hiroshima and Nagasaki.
"My goal for the past 20-plus years has been to educate students about nuclear history and this trip seemed to me to be a perfect opportunity to do it both intellectually and experientially," Kuznick explained.
For Keni Sabbath, the granddaughter of a Hiroshima survivor, visiting Hiroshima and the Peace Memorial Museum helped her identify with her family's history.
"Walking (into the museum) one of the first things I saw was these figures of children, a mother holding a baby," she told CNN. "These wax figurines have melting flesh on them, and in the background is a real photo of the landscape, the destruction and it was just something out of a horror movie.
"I thought, here's a peaceful city and it was at one time hell."
Survivor testimony key to experience
Many visitors say the testimony of bomb survivors (known as hibakusha) helped them humanize history. The hibakusha have been important players in Hiroshima's peace-centric identity since the immediate aftermath of the bombing, and an important part of the Hiroshima Peace Memorial Museum.
"The hibakusha took their anger and suffering and rather than becoming embittered, they led the fight for nuclear abolition and opposition to war," Kuznick said.
"They committed themselves to turning Hiroshima into a city that was going to bear witness to the need for eliminating nuclear weapons."
Though the number of surviving hibakusha is dwindling, the city is making a concerted effort to document their stories on paper and film.
"Japan is the only place where there is a really vivid example of what the nuclear age means," said Bruce Blair, the president of Global Zero, an international organization dedicated to the elimination of nuclear weapons.
Blair said that the emotional resonance of survivor stories can galvanize people to take a more active interest in nuclear issues.
Originally published August 2014, updated May 2016.