Since 2007, Gaza has been under the control of Hamas, an Islamist group committed to the destruction of Israel.
In response to Hamas's attacks on Israel on 7 October, Israel launched airstrikes on Gazan cities and towns and sent tanks and troops into Gaza. The UN says more than a million people have been forced to leave their homes and hundreds of thousands are struggling to find enough food and water to survive.
More than 1,200 Israelis and foreign nationals were killed during the Hamas attacks on 7 October. More than 14,800 Palestinians - including about 6,000 children - have been killed in Israeli airstrikes and operations since then, according to Gaza's Hamas-run health ministry. It isdifficult for the BBC to verifyexact numbers, but the UN's World Health Organization (WHO) have said they have no reason to believe the figures are inaccurate.
A pause in the fighting to allow the release of some Hamas-held hostages and Palestinian prisoners has also enabled aid convoys to enter Gaza.
The military action on the ground followed three weeks of airstrikes accompanied by a "complete siege" of Gaza by Israel, with electricity, food and fuel supplies cut.
The Israeli Defense Forces (IDF) moved into Gaza from the north west along the coast, the north east near Beit Hanoun and across the middle, south of Gaza City. Armoured bulldozers created routes for tanks and troops, as the Israeli forces tried to clear the area of Hamas fighters based in northern Gaza.
Having cut Gaza in two, the Israelis pushed further into Gaza City, where they faced some resistance from Hamas.
An image released by the IDF shows tanks and armoured bulldozers on the beach near Gaza City. Where there are now armoured vehicles, banks of sand and piles of debris were once food stands, parasols and children splashing in the sea. A photo from last summer shows people making the most of the beach during a hot day in Gaza.
Short pauses in the fighting, for four or five hours each day, allowed civilians to evacuate northern Gaza along the main road to the south.
Before the truce, there were hundreds of Israeli airstrikes each day across Gaza, with Israel claiming to have used more than 10,000 bombs and missiles, causing extensive damage to buildings and infrastructure.
Gazan officials say more than 50% of housing units in Gaza have been destroyed, left uninhabitable or damaged since the start of the conflict.
The map below - using analysis of satellite data by Corey Scher of CUNY Graduate Center and Jamon Van Den Hoek of Oregon State University - shows which urban areas have sustained concentrated damage since the start of the conflict.
They say up to 90,000 buildings across the whole Gaza Strip have suffered damage. But North Gaza and Gaza City have borne the brunt of it - both before Israeli tanks and bulldozers moved in, and since their push into Gaza City. Around half the buildings in the two northern regions are believed to have been damaged.
Despite warning Palestinians to head south of the Wadi Gaza for their own safety, Israel has continued strikes against what it says are Hamas targets in southern Gaza.
Analysis of the damage data from 18-22 November also shows an increase in damage in Deir el Balah and Khan Younis - which residents have been told to evacuate.
Analysis of damage outside urban areas, suggests dozens of agricultural greenhouses have been damaged or destroyed and fields peppered with visible impact craters, affecting Gaza's ability to grow its own food.
Before the truce, Israel had allowed some humanitarian aid into Gaza, although aid agencies said it was nowhere near enough.
The UN estimates about 100 lorries carrying aid are required each day just to supply the essential needs of those in Gaza but less than half of that has been allowed in. Even before the current conflict, about 80% of the population was already in need of humanitarian aid.
Despite the increase in food aid being brought in through the Rafah crossing, many people still lack food and fuel to cook.
Israel says it will now allow 70,000 litres of fuel a day to be brought in from Egypt. The fuel will be used for food distribution, generators at hospitals, water and sanitation facilities, shelters, and other critical services. But the UN says it is well below the minimum needed for essential humanitarian operations.
Staple foods such as flour, eggs, dairy products and bottled water are now unavailable in most shops and markets and cooking basic food is difficult because of the lack of fuel. The UN said people are said to be resorting to eating unconventional combinations such as raw onion and uncooked aubergine.
The UN reports no bakeries are open in the north of Gaza because they have either been damaged or lack fuel, flour and clean water.
Israel cut off much of its supply of clean water to Gaza after the Hamas attacks on 7 October, and there are increasing concerns over dehydration and waterborne disease from polluted sources and lack of sanitation services.
Supplies of drinking water via two pipelines from Israel have been restored and fuel deliveries mean some desalination plants to provide fresh water and sewage pumping stations have started operating again.
The WHO sets the minimum requirement for daily water needs at 100 litres per person - to cover drinking, washing, cooking and bathing. Before the conflict, the average consumption in Gaza was about 84 litres, with only 27 litres of that considered suitable for human use.
Currently, the WHO estimates the average water consumption in Gaza is just three litres per person.
Healthcare facilities have been damaged across Gaza and left unable to function as a result of bomb damage or lack of fuel. Major institutions, like hospitals, have back-up generators, but the blockade means no fuel to run them once existing supplies run out.
The BBC's Rushdi Abualouf says patients died at Gaza City's largest hospital, al-Shifa, because there was no electricity, no water and not enough medicine. He said there was no fuel for generators to power vital equipment, including incubators.
The UN's OCHA agency says the small hospitals that are still operational in northern Gaza are under immense pressure and urgently need supplies and staff.
Israeli authorities have called for the evacuation of all hospitals in northern Gaza but the WHO says this would be a "death sentence" to patients, given that the entire medical system is collapsing and hospitals in southern Gaza cannot admit more patients.
Gaza's power grid was left without electricity after its sole power plant closed and supplies from Israel were suspended.
As of 21 October, about 80% of buildings, schools and health facilities in Gaza were likely to have been without power. The only buildings with electricity were those with generators, such as hospitals and UN shelters, and fuel for many of those has run out.
These satellite images show the difference - with about 90% night-time loss of light in some areas. Most of the bright spots still visible on 21 October were hospitals.
The Gaza power plant, in Deir al-Balah just south of the evacuation area, shut down on 11 October after running out of fuel.
According to the UN, just over 75% of Gaza's population - some 1.7 million people - were already registered refugees before Israel warned Palestinians to leave northern Gaza.
Palestinian refugees are defined by the UN as people whose "place of residence was Palestine during the period 1 June 1946 to 15 May 1948, and who lost both home and means of livelihood as a result of the 1948 War". The children of Palestinian refugees are also able to apply for refugee status.
More than 500,000 of those refugees were already in eight crowded camps located across the Strip.
As two of those camps, Jabalia and Shati, are in the evacuation zone, this has put the other six under increased pressure.
Following Israel's warning to evacuate the north, the number of displaced people has risen rapidly and there are now 1.7 million who have fled their homes since 7 October, according to the United Nations.
On 13 October, Israel warned civilians to evacuate the area of Gaza north of the Wadi Gaza riverbed, ahead of an invasion by the Israeli military.
The evacuation area included Gaza City - which was the most densely populated area of the Gaza Strip. The Erez border crossing into Israel is closed, so those living in the evacuation zone had no choice but to head towards the southern districts.
Before the truce,  the IDF had paused fighting for up to five hours each day to allow more civilians to use the evacuation route to the south.
With 2.2 million people in a relatively small strip of land, Gaza has one of the highest population densities in the world.
The largest urban area in the south is Khan Younis, but thousands of people who have fled the fighting are already sheltering there in schools, hospitals and tents.
The IDF recently warned Palestinians that even Khan Younis was not safe and they should move further west to a so-called"safe area" at al-Mawasi, a thin strip of mainly agricultural land along the Mediterranean coast, close to the Egyptian border.
On average, there are more than 5,700 people per sq km in Gaza - very similar to the average density in London - but that figure was more than 9,000 in Gaza City, the most heavily populated area.
The UN warns that overcrowding has become a major concern in its emergency shelters in central and southern Gaza, with some housing at four times its capacity. The Khan Younis Training Centre is the most crowded shelter, with about 22,100 people - 10 times what it should be able to host.
Many of these emergency shelters are schools and in some there are dozens of people living in a single classroom. Men and older boys are having to sleep outside at night.
The repeated conflicts between Palestinian militants and Israel have left many people in Gaza without adequate housing.
Extended families live in overcrowded, low-quality, insecure buildings, with the Norwegian Refugee Council estimating that more than 120,000 were living in homes that had no windows, safe roofs or doors.
Palestinian officials say the current Israeli air strikes have destroyed more than 40,000 homes - adding to 2,200 yet to be rebuilt from previous conflicts since 2014.
Another 72,000 which were damaged but not destroyed in 2014 had not received any financial help with repairs.
The loss of those homes compounds the ongoing shortage of housing in Gaza. The Global Shelter Cluster estimated that, even before the current destruction, 120,000 units needed to be built in Gaza to provide everyone with shelter.
Civilians have little hope of being able to leave Gaza to escape the conflict, with only a limited evacuation of foreign nationals permitted via Egypt.
Before the attack by Hamas, there were only two crossings allowing travel into and out of Gaza - with most former border points having been closed for years.
Palestinians are banned from leaving Gaza via Israel unless they obtain an Israeli-issued exit permit. The permits were limited to day labourers, businesspeople, medical patients and their companions, and aid workers.
The entire 60km-long border with Israel is guarded by a perimeter fence with "no-go" areas extending up to 100m (330ft) from the fence itself and only farm workers are allowed within 300m.
Those wanting to leave Gaza into Egypt via the Rafah crossing had to register with the Palestinian authorities several weeks in advance and apply to Egypt, which imposes limits on numbers and severe security controls.
Now, Israel has indefinitely shut the Erez crossing, while the Egyptian-controlled Rafah border crossing in the south has been closed due to Israeli airstrikes near the gate on the Palestinian side.
The latter had prevented humanitarian aid, including food, water and medicines, crossing from Egypt into Gaza.
During the last two decades, to try to get round the blockade, Hamas has built a network of tunnels which it uses to bring goods into the Strip from Egypt and also as an underground command centre.
Israel says the tunnels are also used by to smuggle weapons and move around out of sight. It frequently targets them with airstrikes.
During a conflict in 2021, the IDF said it had destroyed more than 100km of tunnels in air strikes. In response, Hamas claimed the tunnel system stretched for 500km and that only 5% had been hit.
Gaza has one of the world's youngest populations, with almost 60% of the population under 25 years old, according to the Palestinian Central Bureau of Statistics.
That compares with just over 20% in London, where according to data from the 2021 census, more than 65% of people are aged between 25 and 64.
More than 80% of the population lives in poverty in Gaza, where unemployment levels are among the highest in the world, reaching 45% in 2022.
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Home to 2.2 million people, the Gaza Strip is a densely populated enclave, 41km (25 miles) long and 10km wide, bounded by the Mediterranean Sea on one side and fenced off from Israel and Egypt at its borders.