Four weeks on from the time Malaysia Airlines flight MH370 took off, the mystery of the plane's disappearance remains as deep as ever.
International Air Transport Association chief Tony Tyler spoke for many this week when he said there was "disbelief" that the plane "could simply disappear".
And everyone will echo his sentiments that a plane "must never again go missing in this way".
The four weeks since the plane flew off from Kuala Lumpur have seen non-stop speculation, plenty of theories and an intense search of vast amounts of ocean.
Many countries and top politicians have been involved, with everyone trying to be as reassuring and as informative as possible.
Sometimes it has seemed there has been a break through in the search, only for hopes to be dashed. There has been talk of hijacking, sabotage, pilot error, and plane malfunction, while police have conducted more than 170 interviews with family members of the pilots and crew members.
The search for the plane has been of epic proportions, with nations united in their determination to track down the aircraft.
First, seas around Vietnam were scoured. Then several areas in the Indian Ocean west of Australia were examined, with the area finally narrowed down to an 85,000sq mile area around two-and-a-half hours flying time from Perth in Western Australia.
Through all this, the families of those on board have suffered the most. For a time some harboured hopes that, after all, their loved ones were safe and that the plane had diverted, for some reason, to dry land.
For days the conflicting news of the plane's whereabouts caused anger among the families. Eventually they were told that the plane had crashed in the southern Indian Ocean and there were no survivors.
But as long as no wreckage has been found, the agony goes on for those with loved ones on board, especially as there has been speculation that the exact cause of the tragedy may never be known.
In the meantime, Malaysia's prime minister Najib Razak has said that the search will not stop until answers are found, while Australian premier Tony Abbott has described the search as "the most difficult in human history".
What are sure to emerge from the MH370 tragedy are improvements to aircraft tracking and passenger data. As Mr Tyler said: "Accidents are rare, but the search for MH370 is a reminder that we can never be complacent on safety."