Israel has called up 360,000 army reservists in the wake of Saturday's assault by hundreds of Hamas gunmen.
When the declaration of war came, the response was swift and overwhelming.
Most were already in Israel. Many that weren't have dropped everything to answer the call.
Oren Saar is based in the U.S. His children think he is on a business trip to Israel.
"It's such a pivotal and important moment in the life of the Israeli state that, as an Israeli citizen and someone that was born and raised in Israel and someone that loves this country, you can't just sit, you know 5,000 miles away in New York and watch the news."
It is Israel's largest compulsory mobilisation since the 1973 Yom Kippur War.
While many foreign carriers have cancelled flights to Tel Aviv, Israeli airlines have added flights on foreign routes to bring people back, while the military dispatched transport planes to some European cities to collect soldiers.
Nimrod Nedan, a 23-year-old studying medicine in Lithuania, said friends and relatives died or were missing as a result of the surprise Hamas attack, spurring him to action.
"I myself have two friends who are right now missing and their location is not known. They have been in Nova festival, of the Sukkot, down in the south, which has been attacked by the terrorist group of Hamas. I have a friend who died on my battalion. And I have a family member who also died doing fighting for his home to save his wife and children."
Military service is compulsory for the majority of Israelis when they turn 18. After this, most can be called up to reserve units until the age of 40, or even older, in case of national emergency.
In times of war, they fight alongside the regular troops.
Yonatan Bunzel only finished his military service this year, making him exempt from immediate reserve duties.
He was in India celebrating the end of his service when Hamas struck and despite not being obliged to return, he packed his bags and headed home, five months ahead of schedule.
"I served at the Golani unit and most of the soldiers who had fallen are from my unit, so I know a lot of people who had fallen. So immediate reaction of course was shock and I didn't know exactly what to do. But after a few hours my mind had cleared and I just knew I had to go back home, save my country, help my people and give my part."
