Where is the Malaysia Airlines Boeing 777-200ER? This is the multi-million ringgit question on everyone's mind, from the loss-making national carrier to Putrajaya; plane-maker Boeing and the rest of the world.
The largest and most expensive search and rescue operation in aviation history has failed to detect any physical clue regarding MH370's final location after it vanished from civil and military radars less than two hours after taking off.
The search started in the South China Sea, went across the Malay peninsula to the Straits of Malacca, the Andaman Sea and finally the southern part of the Indian Ocean.
But nothing has been found, except electronic signals that have tracked its flight path to the part of Indian Ocean near Australia.
Clues and answers
Several families of the 227 passengers on board the plane have targeted to raise US$5 million on the crowdsourcing site Indiegogo for a reward to find answers to the missing flight MH370. The fund is a week old and has raised some US$34,000 with 25 days to go to reach its goal.
Malaysian and Australian authorities have started to call tenders for private firms to take part in the next phase of the search, with each country to split the final bill.
Putrajaya has said that national oil firm Petronas and defence firm DRB-Hicom Defence will fund the hunt for flight MH370. The government has also said that Malaysia has spent RM27.6 million thus far on the first phase of the hunt.
The hunt for MH370
In the early days of the flight's disappearance, over 20 countries came together to offer assistance in the form of equipment and manpower to comb the South China Sea.
There were several false alarms, including oil slicks spotted in the South China Sea and possible debris. However, checks later revealed that neither the oil nor the debris originated from flight MH370.
Imagery from satellites of several countries spotted suspected debris in several areas of the South China Sea but it turned out to be false leads.
The search later expanded to the Malay peninsula, the Straits of Malacca and northern Indonesia, all far from MH370's flight route to Beijing.
After some two weeks of searching the South China Sea without getting anything, the Malaysian authorities called off the hunt in that part of the region and sought help of experts from the United States and United Kingdom to find the missing plane.
Final resting place?
Prime Minister Datuk Seri Najib Razak then disclosed that data from UK satellite operator Inmarsat revealed that the plane could have either flown along the northern or southern corridor of the Indian Ocean.
Search and rescue operations were then redeployed along these two corridors to locate the missing MH370 before further analysis pinpointed the southern arc as the most likely flight path taken by the Boeing 777-200ER, which is rated as one of the world's safest aircraft.
Australia took charge of the operation, establishing the Joint Agency Coordination Centre (JACC) and putting retired Air Marshal Angus Houston in charge. Despite the rough weather and some of the harshest ocean conditions, search teams doggedly continued searching with underwater submersible deployed.
Despite the millions of dollars spent, massive tracts of land and ocean searched, and sophisticated equipment deployed, not a single clue to MH370's whereabouts was unearthed.
At the end of May, Australian authorities announced that the area searched in the Indian Ocean could be discounted as the final resting place of the aircraft.
Hijack or terrorism?
Recently, English tabloid Daily Mirror published 634 possible landing points for flight MH370 in the event that it had been hijacked. It was estimated that the plane could have flown another 2,200 miles after it vanished from radar.
The possible runways for flight MH370 to land are spread as far north as Pakistan to as far south as the west coast of Australia or even Japan, the Daily Mirror reported.
Other remote locations include Micronesia, Mongolia and the Maldives.
In the first few weeks of the search, it was also revealed that two passengers on MH370 had boarded the flight using stolen passports, which put the Malaysian Immigration Department under scrutiny.
Italian Luigi Maraldi and Austrian Christian Kozel had reported their passports missing in the resort island of Phuket, in Thailand, but their names appeared on the passenger manifest for flight MH370.
Police later revealed that Iranians Pouria Nour Mohammad Mehrdad, 18, and Delavar Seyed Mohammad Reza, 29, had boarded the flight using stolen passports.
The duo were not found to have any terrorist links but police said they were most probably attempting to migrate to Germany. The discovery of passengers using stolen passports made headlines and raised questions about security at the Kuala Lumpur International Airport.
But all that has been nearly forgotten as only one question remains 100 days after the plane and all aboard vanished: where is MH370? – June 15, 2014.