It is the greatest mystery in aviation history.
Today, 100 days since it vanished on a routine flight from Kuala Lumpur to Beijing, there are still no answers to the fate of Malaysia Airlines flight MH370 and its 239 passengers and crew.
Malaysia - which has copped heavy criticism for the delays and confusion surrounding what many say was a bungled initial search - vowed there would be no let-up in the search.
"We cannot and will not rest until MH370 is found," Acting Transport Minister Hishammuddin Hussein said. "We cannot and will not abandon the families of the crew and passengers of MH370."
He expressed gratitude to Australia, China and other countries that had joined the search, which remains focused on the southern Indian Ocean.
"Indeed, as the search transitions to a more challenging phase, we reaffirm our commitment with renewed vigour to locate the missing MH370," Hishammuddin said.
And he said that despite the criticism, "Malaysia will be credited for doing the best to our abilities under near-impossible circumstances and history will judge us favourably for that".
Malaysian Prime Minister Najib Razak reiterated Malaysia's commitment to the search.
"On this hundredth day since MH370 went missing, remembering those on board and their families," he said on his Twitter account.
But their words were of little comfort to the relatives of the missing passengers, including Gao Yongfu, the wife of one of the 154 Chinese passengers on board. Since March 8 - the day MH370 disappeared with her husband, Li Zhi, on board - the Tianjin woman has kept a diary of her sometimes conflicting emotions.
The diary - excerpts of which are published in the Post today - chronicles the increasing confusion, anxiety and despair of a wife who may never know how her husband died.
Yet Gao refuses to give up on a miracle. "As long as there's a sliver of hope, I won't give up on you," she writes in one entry.
Counting the cost of the hunt for missing flight MH370
Malaysia and Australia have yet to agree on how they will split the cost of searching for the missing jet.
Malaysian and Australian officials discussed cost-sharing last week in the Australian capital, but Australian Transport Minister Warren Truss declined to say on Sunday whether the country was even considering an even split of the bill for a search that will take months, if not years, and cost tens of millions of dollars at a minimum.
"I don't want to give any indication as to where it's likely to end up," Truss said. "We are talking about this with the Malaysians and other countries who have got a key interest."
Canberra expects to spend A$90 million (HK$655million) on the search by July 2015. But the actual cost to Australia will depend on how quickly the plane can be found and how much other countries are willing to contribute. And a legal expert said Australia's obligations were murky because of the unprecedented nature of the plane's disappearance.
Countries are continuing to negotiate on how to fund the next phase of the sonar search of almost 56,000 sq km of seabed beneath water up to 7km deep.
Countries involved in the search, including Malaysia, Australia, the United States, China, Japan, Britain, South Korea and New Zealand, have carried their own costs to date. But Malaysian government lawmaker Jailani Johari, chairman of Malaysia's liaison, communication and media committee, told reporters in Kuala Lumpur last week that future costs "will be shared 50-50" between Malaysia and Australia.
The job is much more difficult than another complex and challenging search it is often compared to: the hunt for Air France flight 447. Though debris from that aircraft was found within days, it took two years to recover the black boxes from the plane, which crashed off the coast of Brazil in 2009, killing 228 people.
The French government, the airline and aircraft manufacturer Airbus paid for most of the underwater search and recovery efforts.
Truss declined to say whether the flight 447 precedent featured in the current funding negotiations, but said the question of who should pay for what under the Chicago Convention was "quite complex."
Australian National University international law expert Don Rothwell said the Chicago Convention was not clear on Australia's financial responsibility.
He said Malaysia had responsibilities as the country where the state-owned airline is registered, while Australia had responsibilities towards aircraft in its air space and search and rescue zone. Complicating matters is that the search is in Australia's zone only because the aircraft went dramatically off course.