As thousands of Gazans made the journey back to their neighbourhoods following the ceasefire, many of them already knew their homes were in ruins.

The prospect of rebuilding homes, businesses and all the institutions and services needed for a return to normal life in Gaza is daunting by any measure: the UN estimates that the damage amounts to $70bn.

As Prof Andreas Krieg, a Middle East security expert from King's College London, says: It's worse than starting from scratch - here you aren't starting in the sand, you are starting with rubble.

The level of destruction on the strip is now in the region of 84%. In certain parts of Gaza, like in Gaza City, it's even up to 92%, says Jaco Cilliers, UN Development Programme special representative for the Palestinians.

This damage has created colossal amounts of rubble. Assessments by BBC Verify based on recent satellite data suggest there could be over 60 million tonnes of debris waiting to be cleared in Gaza.

Any process of post-conflict reconstruction must begin by clearing the remnants of war.

Clearing the rubble

The many millions of tonnes of rubble now littering the Gaza Strip are not just piles of concrete and twisted metal. They also contain human remains and unexploded bombs.

From a safety and humane perspective, the first thing you have to do is make the sites that have been bombed-out safe, says former JCB executive Philip Bouverat.

There follows a process of sorting, separation and crushing the debris. After materials like plastic and steel are removed, the remaining concrete can be ground up and reused.

This will lay the foundations of construction, but building efforts will require the mass import of materials.

This isn't going to be done by trucks coming across the border. The first thing we need to do is build a deep-water port, because then you can bring thousands of container-loads in, Mr Bouverat added.

When the sites are cleared, then essential services such as water, sewerage and electricity can be restored, he says.

Water and sewerage

Clean water is a major immediate need for Gazans. According to estimates from Unicef, more than 70% of the territory's 600 water and sanitation facilities have been damaged or destroyed since 7 October 2023.

After the recent announcement of a ceasefire, Israeli soldiers posed in front of a wastewater treatment plant in Gaza City that had been set on fire. The damage came just before Israel's military withdrew from a position near this infrastructure.

Wastewater treatment is critical for preventing the build-up of sewage and the spread of disease. Doctors have said Gaza has high rates of diarrhoeal diseases, which can kill children, and a risk of cholera in some areas.

In satellite imagery, you can see damage to the bio-towers of the Sheikh Ejleen wastewater treatment plant, which are the main components used for treating sewage.

Housing

Over the course of the war, the UN's satellite centre Unosat estimates a total of 282,904 houses and apartments across Gaza have been damaged or destroyed.

Gaza City's Hamas-run Municipality has said that 90% of its roads have also been damaged.

According to Shelly Culbertson, a senior policy researcher at the Washington-based think tank, RAND Corporation, the rebuilding of Gaza's housing could take decades.

If you rebuild now the way they did in 2014 and 2021 it will take 80 years. If there's good planning, it could take less time, she said.

Good planning is designing camps that can turn into neighbourhoods and helping people move back into and rebuild damaged homes.

Power and Agriculture

Gaza's power system was under strain before the current war. Rolling blackouts were frequent prior to the conflict, with frequent electricity shortages.

The satellite image analysis shows significant destruction in agricultural areas where 4 sq km of crops have been wiped out, exacerbating the food insecurity issues facing Gaza.

Education

About half of Gaza's population before the war was aged under 18, making the necessity for rebuilding schools crucial for any return to standard life.

The UN relief agency for Palestine, Unrwa, which once operated 288 schools in Gaza, says 91.8% of all school buildings will require full reconstruction.

Higher education institutions were also hit hard, with notable sites like al-Azhar University and Israa University being destroyed.