The past few weeks have seen a steep rise in tensions between Israel and Palestine, following the tragic death of three Israeli teenagers -Gilad Shaar, Naftali Fraenkel and Eyal Yi frach and subsequent revenge killing of a Palestinian teen Mohammed Abu Khdeir. The ultra nationalist zeal instigated by these recent events has led to a very grim situation in the region.

Israeli military re-launched its offensive in Gaza, after Hamas’ military wing rejected an Egyptian-brokered truce between the two sides.

So far the violence has cost 213 lives and led to more than 1,200 injuries in Gaza. The overwhelming number of civilian dead, including children, has come from air strikes. Israel argues its offensive is targeting the homes of Hamas leaders and buildings allegedly used to store weapons and as meeting points for militants. But despite its claims, the international community, including many of Israel’s allies, has expressed concerns about the growing civilian death toll in Gaza.

10 crucial Facts to understand the Israel-Gaza crisis-

1 History of Gaza Strip-

Before Israel occupied Gaza, it was controlled for some years by Egypt, which borders Gaza on the west. Israel took it from Egypt during the 1967 war between the two countries, and until 2005 it occupied the Gaza Strip in the same way that it has occupied the West Bank through today.

2 Gaza City is among the most densely populated places in the world.

Gaza City is the 40th most densely populated urban area in the world, putting it on par with some Asian mega-cities.

This large population size makes it very hard for Israel to bomb from the air without hitting civilians. Hamas also places rocket emplacements inside civilian population centers, so Israeli aerial offensives inside Gaza are basically guaranteed to kill lots of non-combatants no matter how much Israel attempts to avoid it.

3 Until 2005, Israel occupied Gaza in the same way that it occupied the West Bank. That included Israeli military bases and settlements, communities of Jews living inside Palestinian territory.

In 2005, Israeli Prime Minister Ariel Sharon decided to withdraw from Gaza. Sharon, a longtime hawk and skeptic of Palestinian independence, had concluded that the Israeli occupation was no longer in Israel’s interest. Sharon withdrew Israeli outposts and uprooted about 10,000 settlers. It was a hugely controversial move inside Israel, particularly on the political right — the current Israeli Prime Minister, Benjamin Netanyahu, quit the government in protest.

4 Hamas is part of an international Islamist movement and doesn’t recognize Israel.

Hamas is, according to its charter, the Palestinian branch of the Muslim Brotherhood — an Islamist group that operates around the Muslim world, and one that nominally ran the Egyptian government for about a year recently. Hamas isn’t controlled by the Egypt-based brotherhood leadership, but they have close ties. Unlike many Brotherhood branches, though, Hamas also has a militant wing: the Izz ad-Din al-Qassam Brigades.

Hamas and Israel’s long history of antagonism — Hamas conducted a significant number of suicide bombings inside Israel during the early 2000s — is a major contributor to the current crisis. Hamas and Israel refuse to negotiate openly and directly, and neither trusts the other even a little bit. As such, even small provocations have the potential to escalate rapidly.

5 Hamas was democratically elected by Palestinians.

Hamas sees itself as the representative of the Palestinian people — and, in a sense, they’re not totally wrong. Prodded by the George W. Bush administration, the Palestinian Authority held popular elections across the West Bank and Gaza for the Palestinian legislature in 2006. Hamas won a slight majority.

6 Israel blockades Gaza, which creates a humanitarian crisis. Gaza has been described as the world’s largest open air prison.

Israel and Hamas have fought multiple wars over Gaza. Since Israel’s 2005 disengagement, Israel and Hamas have fought three separate wars: in 2006, in 2008-9, and in 2012; Israel invaded Gaza in the first two but only bombed in the third. The 2006 war was triggered by Hamas kidnapping a young Israeli soldier, much as the current crisis was triggered by the kidnapping and murder in the West Bank of three Israeli students. Men who Israel believes were Hamas operatives killed them.

7 Hamas gets a lot of rockets from Iran.

Iran is arguably Hamas’ most important international patron. For many years, Iran supplied Hamas with cash and advanced rockets. But, in 2012, Hamas and Iran went through something of a divorce over the war in Syria. Iran backs Syrian dictator Bashar al-Assad, an Alawite Shia, against the popular Sunni rebellion, which the mostly-Sunni Palestinians largely support. Hamas refused to take Assad’s side, so Iran cut off cash shipments in late 2012.

Iranian involvement complicates the current war significantly. It’s possible a secondary Israeli objective is to send a message to Iran that it can’t get at Israel through Hamas anymore. On the other hand, Iranian support makes it harder for Israel to starve and bomb Hamas into submission.

8 Tunnels into Gaza are really important — and hugely controversial.

Because Hamas can’t get much through the Israeli blockade, they’ve developed an alternative means of resupplying Gaza: tunnels into Egypt. Gazans dig under the Egyptian border and pop out past border guards on the other sides. Smugglers supply them with goods that Israel can’t or won’t let through.

These tunnels serve both Hamas and Gaza civilians. Hamas and its fellow militants use them to bring in weapons, components for homemade rockets, and whatever else they need to fight and, in Hamas’ case, govern. Civilians bring in medicine, food, and whatever else they want that doesn’t get through the Israeli blockade.

9 Egypt controls the only above-ground crossing into Gaza that isn’t Israeli. There’s only one major supply route to Gaza that isn’t a tunnel or Israeli-controlled: the Rafah crossing into Egypt. Currently, Egypt heavily restricts the flow of people and goods in and out of the crossing. The Muslim Brotherhood is the leading Egyptian opposition group, and the Egyptian government has little desire to help out their Palestinian brethren in Hamas.

10 Children casualties

A leading human rights organisation has warned a fifth of those who have died in the nine-day conflict are children. In light of the violence, the group predicts that at least 25,000 children will need psycho-social support to cope with the trauma they have experienced since violence in the region restarted last Tuesday.