Yahya and his twin sister Nabila were playing in the ruins of their house in Gaza City when they came across a round object.
Their grandfather Tawfiq Shorbasi said they thought it was a toy.
When they reached for it, all it took was one touch and it went off.
Now the six-year-olds are lying in hospital beds, severely injured by what has been described as unexploded ordnance.
"Their lives have been ruined forever," Mr Shorbasi said.
Like many Palestinians, the twins' family seized the chance to return to what was left of their home after the ceasefire came into effect on October 10.
People have been sifting through rubble searching for belongings, and for bodies unreachable until now.
But the dangers are far from over.
United Nations specialists estimate about 7,500 tonnes of unexploded munitions may be strewn across Gaza.
A British emergency physician and paediatrician working at one of the hospitals treating the twins said their injuries included a lost hand, a hole in the bowel, broken bones, and potential loss of a leg.
Dr Harriet, who declined to give her last name because she was not authorised by her employer to speak to the media, said the children were in a relatively stable condition after emergency surgery.
But concerns remain for their recovery due to the lack of medicine and medical supplies in Gaza.
"Now it's just a waiting game, so I hope that they both survive," she told Associated Press.
"But at this point in time, I can't say, and this is a common recurrence.
"This is the death trap … we're talking about a ceasefire, but the killing hasn't stopped."
Thousands of tonnes of unexploded bombs
The United Nations Mine Action Service (UNMAS) estimates, based on munition failure rates, that between one in 10 and one in 20 weapons fired into Gaza have not gone off.
Other bomb disposal experts, such as Mines Advisory Group director of programmes Greg Crowther, believe the failure rate may be higher than one in 10 in urban centres.
He said bombs did not always detonate when piercing through multi-storey buildings — especially ones that were already damaged.
By October 2024, Israel's military said it had already carried out more than 40,000 air strikes on the Gaza Strip.
Since then, large-scale Israeli bombing has continued, including across Gaza City in mid-September.
There have also been ground strikes and remnants left by Hamas and its allies.
The HALO Trust Middle East director Nicholas Torbet, whose NGO specialised in clearing explosives, said "every single part" of Gaza had been hit by ordnance.
"The sheer scale and amount of it across Gaza is a real risk to civilians," he said in an interview with Al Jazeera.
Gaza's Health Ministry, operating under the Hamas-run government, said five children had been wounded by unexploded ordnance in the past week, including one in the southern city of Khan Younis.
UNMAS said there was "no clear figure" on the number of people injured or killed by unexploded ordnance in Gaza.
The organisation had documented 52 Palestinians killed and 267 others wounded since the war began in October 2023, but said the toll could be much higher.
UNMAS Palestinian territories head Luke Irving said the organisation recorded an average of two deaths per day during the ceasefire in January.
John Shanahan, a former commander of the ADF's counter-improvised explosive device task force and managing director of mine detection technology firm MRead, said threats would be everywhere.
He said explosive remnants of war would be hidden under rubble and inside buildings, often resembling regular objects and debris.
"Kids are attracted to them because they are shiny," Mr Shanahan told the ABC.
"What is safe and what is hazardous … [is] often very difficult to see."
Clearance could take 30 years
Humanity & Inclusion explosive ordnance disposal expert Nick Orr said clearing the surface of Gaza could take "20 to 30 years".
He described the enclave as a "horrific, unmapped minefield".
Mr Orr, who has been to Gaza several times during the conflict, is part of his organisation's seven-person team set to begin identifying war remnants in essential infrastructure such as hospitals and bakeries this week.
"If you're looking at a full clearance, it's never happening, it's subterranean," he said.
"We will find it for generations to come."
There are several issues that make clearing Gaza particularly challenging.
It was a dense urban area, with narrow streets and damage to nearly every building, Mr Shanahan said.
"That means limited access for machinery and high risk of secondary collapse," he said.
Mr Irving told a United Nations briefing last week that 560 unexploded ordnance items were found during the current ceasefire, with many more under the rubble.
"As expected, we're now finding more items because we're getting out more; the teams have more access," he said.
Two years of war had left up to 60 million tonnes of debris across Gaza, he said.
Mountains of rubble and high-tech weapons
Mr Shanahan said it would be difficult to detect munitions buried under the rubble with available technology.
And removing the layers of debris comes with its own set of risks.
"There has been the use of the full range of weapons systems," he said.
"You have unexploded aircraft bombs, tank rounds, artillery, air-dropped precision munitions that failed to function, plus improvised hazards."
Some weapons systems detonate with a pressure-activated trigger.
But more modern munitions can be fitted with sensors and do not even need to be touched to explode.
Mr Shanahan said Israel could have used a "new" weapon, or "high-tech US" munitions.
"These are all modern munitions," he said.
"It is far more complex than we've encountered up to now."
Teams push for greater access
The UN and various international explosive clearance teams are hoping to rapidly scale up operations.
The HALO Trust is calling for immediate access in Gaza for at least 100 experts.
Mr Irving from UNMAS said the whole sector needed to scale up.
"I'm pushing very hard as a lead for UNMAS to make sure people can get in, other organisations can get in, and we all make sure we're efficient at hitting the areas [where] we need to have maximum benefit for people as life returns to normal," he said.
Educating locals about the risks of explosive ordnance and how to identify them is among the top priorities.
Mr Irving said teams would also be mapping out high-risk areas, as well as key roads and neighbourhoods.
The UN, The HALO Trust and various organisations have been pushing for more funding to sustain efforts now and into the future.
Mr Shanahan said large-scale explosive disposal efforts could be very successful, but it depended on donor funding.
"Compared to where we've operated before, like Angola, Gaza is incredibly complex," he said.
"The donor levels required for these tasks are on another level — you're not talking a few million here and there, you're talking vast amounts of money."
ABC/Wires
