Lime mortar is like the glue that holds bricks and stones together. It's made by mixing a special kind of powder called lime with some sand and water.
Lime is made from a kind of rock called limestone. It's pretty special because when you mix it with water, it doesn't get hard right away like other types of cement. Instead, it slowly turns back into rock over time. This makes it great for use in buildings that need to last a long time because it won't crack or crumble as quickly as other types of cement.
Another cool thing about lime mortar is that it's pretty flexible. This means that when the ground underneath a building moves (which can happen if there's an earthquake or just natural movements over time), the lime mortar can bend and move with it so that the building doesn't fall apart.
So, lime mortar is like a super strong, slow-drying glue made from rocks that can bend and move with a building over time. Pretty cool stuff!