Megisti Lavra the older monastery.
entrance
aerial photo
photo from sea
Great Lavra is the oldest, with a life of 1060 years,
so there is not only one architecture.
Inside yoy may see from ancient Greek elements, to Roman Persian aven Arabic and Late medieval to Gothic elements,
that has to do with the era that buildings were build, donations, even era of reconstruction damaged sectors,
the city structure follows typical of monasteries, which is nothing else than the older Greek Oikia/small palace, which evolute to Roman block of multihousing,
you may say a Roman block, or a small fortified city,
the 2 videos bellow show us the interior.
Here is a 360 view walk of monastery.
https://mountathos360.com/en/360/iera-monh-megisths-lauras/