Is it permissible for female students to go on a school trip to the ruins of Babylon, a distance of 40 km, knowing that their residence is in the same governorate?

It is absolutely impermissible for an adult or adolescent woman to travel without a mahram, due to the Prophet's (peace be upon him) saying: "It is not lawful for a woman to travel except with a mahram." This includes anything that is considered travel. However, if the movement is not عرفًا (customarily) considered travel, then there is no objection to them going out, provided they adhere to the Islamic regulations, such as wearing the hijab, avoiding impermissible mixing, and ensuring safety from fitna (temptation/strife). As for young girls who have not reached or are not close to puberty, they are permitted to travel without a mahram.