The deaths of 16 teenage students and two young teachers in the Germanwings Airbus A320 plane crash in the French Alps left the lakeside town of Haltern am See in a state of shock on Wednesday, with the German nation sharing in their mourning and grief. A tranquil and tidy town of 37,000 that until Tuesday seemed to be a haven from the world's dangers, Haltern am See came to a halt after news that 14 girls, two boys and two teachers on a Spanish language exchange programme were not coming home. "On Tuesday last week we sent off 16 happy, young people with two happy, young teachers on a journey," said Ulrich Wessel, headmaster of the Joseph-Koenig-Gymnasium high school. "It was meant to be a journey full of joy, a school exchange that we've been doing for six years. It ended in tragedy," added Wessel. "Our school will never be the same again." French investigators searched for clues as to why the German Airbus flying from Barcelona to Duesseldorf ploughed into an Alpine mountainside, killing all 150 on board. The 16 German students, all about 15 years old, had started learning Spanish at the start of the school year and were picked from 40 applicants to the popular language exchange programme. A group of Spanish students spent a week in Haltern in December. "Someone asked me how many we have at our school. Without thinking, I answered 1,283. There are actually 16 fewer now," said Wessel, who was close to tears. "It's all so horrible that I can hardly find words." In all, 72 Germans were killed in the crash, the first major air passenger disaster on French soil since the 2000 Concorde accident just outside Paris. Spanish officials said 49 Spaniards were among the victims. French President Francois Hollande was being joined by Germany's Angela Merkel and Spain's Mariano Rajoy to pay their respects to the victims and to meet search teams at their base in the nearby village of Seyne-les-Alpes later on Wednesday. "LIFE'S PLANS GONE" There was a pall hanging over the closely knit town north of former mining centres of Dortmund and Gelsenkirchen. The despair was amplified by heavy low-lying clouds on a chilly spring day. Crowds of students, some sobbing and many dressed in black, gathered in front of their high school to mourn. Some placed flowers on the steps next to the hundreds of candles in red glass left by mourners at the three-storey cement building. Local residents huddled among themselves, talking quietly and trying to avoid the journalists from across Germany and overseas who had descended on their once little-known town. "This is a pain that no one, not even the greatest power on earth, can stop - we can only try to accompany," said Sylvia Loehrmann, education minister of North Rhine-Westphalia state. Schools across the state will hold a moment of silence for the victims on Thursday and flags across Germany were lowered to half mast. Some 50 trained experts were at the school to help the children and teachers cope. The headmaster said the two teachers were also young - one got married last year in October and the other was engaged. "From one minute to the next, their life's plans were gone - they'll leave a big hole at our school," Wessel said. "It's a deep wound to lose 16 children and two teachers that will take long to heal and will leave deep scars." Across Germany, which takes pride in a safe and efficient transport system, the sorrow was exacerbated by the loss of so many of Haltern's bright youngsters bound for university. Tiny Schroers, a 65-year-old flying home to Duesseldorf after celebrating her grandson's birthday in Berlin, said it felt strange to travel by plane: "I can't help thinking about all those young people who died." She had thought about cancelling her flight and driving home but decided to fly after all: "Germany is a very safe country. But yes, I am a little bit nervous." The sorrow could also be felt at Duesseldorf airport, where people lit candles and placed flowers against a metal support and pinned up messages in German, English and Spanish. "My thoughts are with all the victims and relatives of this terrible air disaster," reads one message on black paper pinned to A pillar. "Keep strong, we're crying with you," reads another.