When Hamas militants staged the worst-ever attack on Israel, they took back into the Gaza Strip 251 hostages, some of them already dead.
A year later, 64 people, including two children, are still in captivity and Israel believes they are alive.
For the Palestinian militant group that rules the Gaza Strip, the hostages are key bargaining chips to negotiate a truce with Israel and seek the release of Palestinian prisoners held in Israeli jails.
Here is what we know about the hostages still held in Gaza.
52 men, 10 women, two children
Of the 251 hostages seized by militants on October 7, 2023, 117 have been freed, most of them women, children and foreign workers.
Most were released during a week-long truce in late November in exchange for 240 Palestinian prisoners held in Israeli jails.
Nearly a year later, Israel believes 64 hostages still held in Gaza are alive.
The army has confirmed 70 others are dead, 33 of whose bodies are still in Gaza.
The military has repatriated the bodies of 37 hostages who either died in Gaza or were killed on October 7 and taken to the territory.
Of the 64 thought to be alive, 57 are Israelis, though some of them have more than one nationality. Another six are Thai nationals and one is Nepalese.
Fifty-two are men and 10 are women. Eleven are military personnel.
Two are children.
The youngest hostage, Kfir, was just eight-and-a-half months old when he was kidnapped. The other is his brother Ariel, who was only four years old when he was taken to Gaza.
Hamas has said the two children are dead, but Israel has not confirmed this.
No proof of life
Since the truce ended on December 1, only seven other hostages have been freed alive, all during Israeli military operations.
With no proof of life, uncertainty remains over whether the 64 are still alive.
The armed wing of Hamas said on August 12 that its fighters had shot and killed an Israeli hostage and injured two others.
Hamas has announced on several occasions deaths of hostages that have not been confirmed by Israel, leaving families in agonising limbo.
Bodies taken to Gaza
On October 7, Hamas militants took several dead back into Gaza with them, including 10 Israeli soldiers’ bodies.
At least 28 other hostages have died in the territory since the start of the war.
Three were killed in error by the Israeli army on December 15, 2023. They were Yotam Haim, 28, Samer El-Talalqa and Alon Shamriz, 26.
The Israeli army accuses Hamas of executing six others in August: Hersh Goldberg-Polin, Carmel Gat, Eden Yerushalmi, Alexander Lobonov, Almog Sarusi and Ori Danino.
They were found dead by soldiers in a tunnel in Rafah, in southern Gaza.
Festival, kibbutz survivors
Most of the hostages were taken during the attack on the Nir Oz kibbutz and on the Nova music festival.
At Nir Oz kibbutz, of the at least 76 hostages taken on October 7, 40 were released alive. Another 20 are still in Gaza and believed to be alive. The remaining 16 are dead.
Only 17 people abducted from the festival are thought to be alive and still being held in Gaza.
Only nine of at least 43 hostages taken from Nova have been released, while 17 others have died.
Whole families
On October 7, whole families were taken to Gaza. For them, the November 2023 truce brought relief but also the heartache of leaving loved ones behind.
French-Israeli children Eitan, Erez and Sahar were freed but their fathers Ohad Yahalomi and Ofer Kalderon are still being held.