Over 250,000 people have fled from the Idlib region in northwestern Syria in just the past two weeks, according to the United Nations, as Syrian President Bashar al-Assad, backed by Russian forces, pushes forward with an all-out assault on the country’s last main rebel-held territory.

It is tragedy on top of tragedy: So many Syrians have been killed, injured, displaced and disappeared that it can be hard to keep track of the timeline. Here’s a review of what’s been happening in Idlib and five other sieges and humanitarian crises that have shaped events in Syria since 2011.

Idlib province

Assad’s forces, backed by Russia and Iran, have reclaimed nearly all parts of rebel-held Syria: The last stronghold is Idlib province, home to 3 million people and largely controlled, until now, by the al-Qaeda-linked rebel group Hayat Tahrir al-Sham.

The Syrian Army’s artillery and Russian missiles raining down around Idlib have sent people fleeing in what aid groups say could become the worst humanitarian crisis yet in Syria’s civil war, now in its ninth year. People are desperate to find food, shelter and medical care — all which they already were struggling to find: Leading up to this escalation, Syrian forces had been targeting Idlib province for months, displacing around 500,000 civilians, many of whom had already been displaced from homes elsewhere in Syria.

In recent weeks, Syrian forces have retaken several villages and now have their eye on a strategic highway and the nearby town of Maarat al-Numan, the largest in Idlib’s southern countryside. The ground and air assault has pushed tens of thousands of scared Syrians to the border with Turkey, which has backed its own rebel groups in Syria and already hosts about 4 million Syrian refugees.

“People, I swear by God, are sleeping in open air under trees and the temperature at night is near freezing,” Shaker al-Humeido, a doctor in Maarat al-Numan, told The Washington Post’s Sarah Dadouch and Kareem Fahim. “I am shocked at the size of the tragedy.”

It’s winter now in Syria, and the cost of fuel around embattled Idlib has doubled since early October, the Guardian reported. That has in turn pushed up the price of food and made it even harder for families scrambling to find safer ground. Remaining hospitals and makeshift clinics are struggling to afford running vital medical equipment.

Eastern Ghouta

For five years, Syrian government forces besieged eastern Ghouta, a suburb of the capital, Damascus. Before the war, Ghouta was known for fertile farmland that served as Damascus’s breadbasket. By April 2018, when Assad’s forces retook control, people were dying from a siege that a 2018 U.N. report called a “medieval form of warfare.”

In the initial months of Syria’s uprising, eastern Ghouta became a rebel stronghold as opponents of Assad took control in 2012. But the at first peaceful uprising began to radicalize into armed conflicts as Assad’s forces responded to protesters with gunfire, arrests, torture and disappearances. Neighboring countries were soon intervening by funding Syrian rebel groups to assert their interests. The most extreme forces on both sides came to dominate the battlefield. Syrian civilians were left to suffer amid a muted international response.

Assad imposed a blockade on eastern Ghouta in 2013. At first, people could survive by smuggling in food, fuel and medical supplies and relying on savings. From there, rebels were also able to launch rockets into Damascus. But the years of siege eroded away life for the nearly 400,000 civilians there. Various deals brokered over the years allowed some aid in and waves of fighters and civilians to leave.

Then in early 2017, Assad’s forces retook strategic parts around eastern Ghouta, cutting off the smuggling routes. By early October they had closed off the last entry to Douma, the main city in the region, strangling the area further. “Back in the days that we had dessert, I used to promise my daughter a piece at the end if she was good,” Layla Bikri, a 26-year-old mother in eastern Ghouta, told The Post in October 2017. “Now when she asks, I give her pieces of corn. A piece of corn each time.”

The spring of 2018 brought weeks of nonstop bombing waves by pro-Assad forces and, according to Syrian doctors and aid workers there, chemical weapon attacks that killed dozens of people. (The Syrian government denies the attacks.) The international community, meanwhile, was largely paralyzed in its response as terrified people sought refuge from the bombardments underground.

By the time Assad retook control, pro-government forces had “laid the longest running siege in modern history, steadily wearing down both fighters and civilians alike through a prolonged war of attrition,” according to the 2018 U.N. report. The United Nations also found that the Syrian government and its affiliated forces and Syrian rebels in eastern Ghouta all committed war crimes during the siege. The report accused Assad of “deliberately starving” and bombing at least 265,000 civilians there, and extremist rebels of crimes such as targeting civilians when firing rockets at Damascus.

Raqqa

Raqqa had once been home to 400,000 Syrians along the northeast side of the Euphrates River. These days it’s notoriously known as the former capital of the self-described Islamic State, which imposed its extremist rule and restricted residents from leaving.

The Islamic State held Raqqa from 2014 until 2017, when U.S.-backed forces retook control of the city. That bloody and grueling battle, fought by the then-U.S.-backed Syrian Democratic Forces (SDF) and bolstered by U.S.-led coalition airstrikes, displaced over 270,000 civilians. It also killed more than 1,600 civilians, according to a report by London-based Amnesty International and the monitoring group Airwars. The months of shelling by U.S.-led forces leveled the city. The Islamic State’s booby-trapping of homes and waves of suicide bombers as it retreated further increased the toll of the battle for SDF fighters and Syrian civilians.

The years under the Islamic State, followed by the bloody campaign to oust it, left residents deeply hurting mentally and physically.

“What you see in their eyes is shock,” Rajia Sharhan, a doctor with UNICEF working with young Syrians displaced from Raqqa, told The Post in 2017. “They’ve survived the bombing and shelling. They’ve been bound to their mother’s chest on the escape and heard the screams over and over. They have already lost their childhood.”

Zabadani and Madaya

The two Syrian towns near Damascus and the border of Lebanon were once full of holiday resorts. Then they came under siege by the Syrian government and allied Hezbollah fighters from 2015 to 2017. By the winter of 2016, people in Madaya were reduced to skeletons and reportedly starving: Some civilians even starved to death, according to aid groups.

Images of hallowed Syrians with protruding bones brought international outrage. But back-and-forths between humanitarian groups and the Assad regime continued to stall the delivery of desperately needed aid. For activists, Madaya became a symbol of how the fraught politics of humanitarian aid were failing Syrian civilians caught in the chaos. Finally, in 2017, remaining civilians and fighters in Madaya and Zabadani were transferred to rebel-held Idlib as part of an exchange with the Syrian government.

Aleppo

Aleppo was once Syria’s largest city and industrial capital. Now it is haunted by the fighting that divided the city for four years, when the west side was under control of the Syrian government and the east side was held by rebel groups, until their ouster in 2016.

The battle for Aleppo is perhaps most associated with the barrel bombs — oil drums filled with shrapnel, nails and other explosives — that Assad and allied forces, including Russia, rained down as part of their bombardments of the rebel side. These bombing campaigns indiscriminately killed hundreds of fighters and civilians and also targeted hospitals.

Throughout the siege, Assad’s forces slowly retook more and more of the rebel-held side. As in other cities, occasional cease-fires and deals allowed for the exit of some civilians and fighters, whose fate could not be guaranteed once in government hands.

Surgeon Mounir Hakimi, founder of the Syria Relief aid group, recalled the state of Syrians who had been among the last to leave eastern Aleppo.

“They looked like hollow shells of people,” he said. “As they climbed off the buses they were exhausted, they were broken. I saw people with bones sticking out because they had no medical care in those final weeks. … Everyone knew it would be bad. But not like this. On that day we saw Aleppo’s living dead.”

Homs

The siege and bombardment of rebel-held Baba Amr on the outskirts of Homs in February 2012 so deeply disturbed renowned war correspondent Marie Colvin that she felt she had to be there and document it despite the perils. The Syrian government’s attacks that month on the western Syrian city killed hundreds. Colvin, along with a French photographer, Rémi Ochlik, were among the victims.

“Hours before her death Wednesday at age 56 in the besieged city of Homs, Syria, Ms. Colvin was interviewed on American and British TV news programs,” Emily Langer at The Post wrote in Colvin’s obituary. “Speaking with CNN’s Anderson Cooper, she described the ‘horrific’ experience of watching a 2-year-old Syrian boy die after a shelling by the Syrian military.”

Homs had been known as the “capital of the revolution,” an homage to how its residents quickly embraced the popular uprising. But Assad and his allies’ bombardment and siege of Homs was one of the first tests in how the war would proceed — and, as history has shown, this script played out again and again in other Syrian cities.

It wasn’t until 2015 that Assad’s forces entirely retook control of Homs and ousted the few remaining extremist fighters and traumatized civilians. In the preceding years, the international community helped to broker occasional cease-fires and aid deals but proved largely ineffective in stopping the bloodshed.