Cave al-Sajdah at Jabal Sela / غار السجدة في جبل سلع

A unique cave in Al-Medina, which Prophet Muhammad slept and rested in, during the Battle of Al Khandaq (Battle of the Trench/ #Khandaq_Battle). It is also called Ghar Al-Sajdah (Cave of Gratitude, also known as: Cave of Banu Haram). The cave is situated on Mount Sela, which is a dark expansive mountain near Al-Masjid An-Nabawi.
During the Battle of the Trench, Muadh Ibn Jabal was searching for the Prophet (SAW). He was informed that Prophet Muhammad, was resting in the Cave of Banu Haram. When he ascended to the cave, he found the Prophet, performing 'Sajdah' (prostration). He decided to wait for him until he finished. However, the Prophet remained in Sajdah for such a long period of time, that Muadh began to fear, that perhaps the Prophet had passed away.
When the Prophet eventually completed his Sajdah, Muadh immediately addressed him: “Oh Messenger of Allah, you remained in Sajdah, for such a long time, that I feared you had left this world.”
The Prophet replied: “Jibreel came to me right here, and said Allah sends you his Salam, and asks what would you like Him to do with your Ummah?" The Prophet replied “#Allah_Knows_Best.” Then after a short while, Jibreel returned with the good news, that “Allah will not harm, or disappoint you, with regards to your Ummah”. When the Prophet heard this, he immediately fell into prostration, and thanked his Lord.
The closest position a slave can assume to their Lord, is in #prostration. So for this reason, the cave was named Ghaar Al-Sajdah.