In this April 17, 2014 file photo, South Korean Coast Guard personnel search for missing passengers aboard the sunken South Korean ferry Sewol in the water off the southern coast near Jindo, South Korea. High school student Cho Eun-hwa, 16, was one of 304 people killed one year ago on Thursday, April 16 in the sinking of the ferry, and among nine whose bodies still have not been recovered. (Photo by Ahn Young-joon/AP Photo)

A combination picture shows Huh Heung-hwan (R) and Park Eun-mi the parents of Huh Da-yoon, a high school student who died in the Sewol ferry disaster, as they pose for a photograph in their daughter's room, as well as details of her belongings, in Ansan April 8, 2015. Park said: “I haven’t thought about anything but finding my daughter. I will never give up until I find her. For a year, every day was like that day, April 16, 2014. The times I laughed about trivial things have became precious moments. I thought living an ordinary life was the easiest thing, but I've realised it is the hardest thing”. Nearly a year after the Sewol ferry sank on April 16, 2014, with the death of 250 students, some families keep their children’s bedrooms intact to remember and honour their loved ones. More than 300 people, most of them students and teachers from Danwon High School, are dead, or missing and presumed dead, after the Sewol ferry sank on a routine trip from the port of Incheon, near Seoul, to the holiday island of Jeju. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Lee Sun-mi, mother of Kim Ju-hee, a high school student who died in the Sewol ferry disaster, as she poses for a photograph in her daughter's room, as well as details of objects, in Ansan April 8, 2015. Lee said: “A thorough investigation has to be conducted. Spring has come and flowers are blossoming, but moms cannot smile. I hope the children who are still missing will be found ... I wish I could bring back my daughter. The world after the tragedy is not the place that I had known”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Eom Ji-yeong, the mother of Park Ye-ji, a high school student who died in the Sewol ferry disaster, as she poses for a photograph in her daughter's room, as well as details of objects, in Ansan April 8, 2015. Eom said: “Every relic of our children is still there. I’d like to find them ... I’d also like to know the truth and the reason why they were not ordered to escape the ferry”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Kim Mi-hwa, mother of Bin Ha-yong, a high school student who died in the Sewol ferry disaster, as she poses for a photograph in her son's room, as well as details of objects, in Ansan April 7, 2015. Kim said: “As I see the children, they are all pretty and precious. All of them have a right to be loved and have dreams. Losing these kids is a tremendous loss for our country”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Jung Hye-suk, mother of Park Sung-ho, a high school student who died in the Sewol ferry disaster, as she poses for a photograph in her son's room, as well as details of objects, in Ansan April 7, 2015. Jung said: “Good children have died because of adults’ faults. The Sewol disaster taught us about the problems of our society and adults should make efforts to fix them, although it’s too late. We have to strive to prevent any reoccurrence of this disaster and to build a culture that cherishes human life. Our children didn’t blame society. They tried hard to save each others’ lives and worried about their families. Don’t we have to learn from the efforts they showed in the last minutes of their lives?”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Jung Bu-ja (R) and Shin Chang-sik, parents of Shin Ho-sung, a high school student who died in the Sewol ferry disaster, as they pose for a photograph in their son's room, as well as details of objects, in Ansan April 9, 2015. Jung said: “I was protesting, asking for an inquiry to find out the real reason why the ferry capsized. Some foreign tourists took photos of me. At that moment, I felt I was an alien, although I live in this country. All I wanted to know was the reason why the crewmen were all rescued but our children had to die”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Kim Young-lae (R) and Kim Sung-sil, parents of Kim Dong-hyuk, a high school student who died in the Sewol ferry disaster, as they pose for a photograph in their son's room, as well as details of objects, in Ansan April 8, 2015. Kim Young-lae said: “A thorough investigation is needed, and wrongdoers should be punished. This kind of accident might happen again, if we don't know why it happened”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Kim Youn-sil, mother of Jeong Cha-woong, a high school student who died in the Sewol ferry disaster, as she poses for a photograph in her son's room, as well as details of objects, in Ansan April 8, 2015. Kim said: “I feel so sorry for Cha-woong and miss him so much. Those children who stayed calm in the ferry at the last moment and worried for us were better than us. I don’t have confidence in my country any more. I want to move abroad, if my oldest child feels okay with it”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Kim Yu-jeong, mother of Jeon Ha-yeong, a high school student who died in the Sewol ferry disaster, as she poses for a photograph in her daughter's room, as well as details of objects, in Ansan April 7, 2015. Kim said: “I wish our country could make us feel like it is protecting us. I want to tell Ha-yeong’s younger sister about my proud country but I can’t these days. We, as adults, have a duty to protect our children. I hope our children grow up well and lead our country in a right direction”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Ahn Myeong-mi, mother of Moon Ji-sung, a high school student who died in the Sewol ferry disaster as she poses for a photograph in her daughter's room as well as details of objects, in Ansan April 7, 2015. Ahn said: “My perspective on my country has changed. I thought my country was good. I prayed for it. However, after the disaster, I couldn’t pray for a while”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Lee Hye-kyung, mother of Jeon Hyeon-tak, a high school student who died in the Sewol ferry disaster, as she poses for a photograph in her son's room, as well as details of objects, in Ansan April 8, 2015. Lee said: “Hyeon-tak's body was discovered on May 1. How could I say even a word in front of such a deep sorrow. I don’t have any passion for my life. I raised him with all my heart. Hyeon-tak, thank you for the life you spent with me”. (Photo by Kim Hong-Ji/Reuters)

A combination picture shows Shin Jum-ja (R) and Jung Soo-beom, mother and younger brother of Jung Hwi-beom, a high school student who died in the Sewol ferry disaster, as they pose for a photograph in Shin's son's room, as well as details of objects in Ansan April 7, 2015. Shin said “Before the accident, my family talked a lot. Now we save our words, trying not to hurt each other. I am eager to see Hwi-beom just once. I wish I could hug him”. (Photo by Kim Hong-Ji/Reuters)

Student identification, letters from a schoolmate and other belongings are seen on a desk in a room belonging to Park Sung-ho, a high school student who died in the Sewol ferry disaster, in Ansan April 7, 2015. His dream was to be a priest. (Photo by Kim Hong-Ji/Reuters)

Pictures are seen in a room belonging to Jeon Ha-yeong, a high school student who died in the Sewol ferry disaster, in Ansan April 7, 2015. Her dream was to be an international aid worker. (Photo by Kim Hong-Ji/Reuters)

Teddy bears belonging to Kim Ju-hee, a high school student who died in the Sewol ferry disaster, lie on a bed in her room in Ansan April 8, 2015. Her dream was to be a doctor. (Photo by Kim Hong-Ji/Reuters)

Pictures hang in the bedroom of Jung Hwi-beom, a high school student who died in the Sewol ferry disaster, in Ansan April 7, 2015. His dream was to be a car designer. (Photo by Kim Hong-Ji/Reuters)

A soft toy is seen between reference books in a room belonging to Kim Ju-hee, a high school student who died in the Sewol ferry disaster, in Ansan April 8, 2015. Her dream was to be a doctor. (Photo by Kim Hong-Ji/Reuters)

A certificate belonging to Jeong Cha-woong, a high school student who died in the Sewol ferry disaster, is seen in his room in Ansan April 8, 2015. He received the certificate from the Haedong Kendo association after he died in the disaster. His dream was to be a Haedong Kendo master. (Photo by Kim Hong-Ji/Reuters)

Eom Ji-yeong, mother of Park Ye-ji, a high school student who died in the Sewol ferry disaster, poses for a photograph with a picture showing her daughter (4rd L, in top line) with her schoolmates when she was 15, in her daughter's room in Ansan April 8, 2015. Her daughter's dream was to be a computer programmer. (Photo by Kim Hong-Ji/Reuters)

A photograph is seen in a room belonging to Jeon Hyeon-tak, a high school student who died in the Sewol ferry disaster, in Ansan April 8, 2015. (Photo by Kim Hong-Ji/Reuters)

A picture of Moon Ji-sung, a high school student who died in the Sewol ferry disaster, hangs in her room in Ansan April 7, 2015. Her dream was to be a flight attendant. (Photo by Kim Hong-Ji/Reuters)