A mole in architecture is like a really long pathway made of rocks and dirt that juts out from the shore into the water. Imagine you are at the beach playing in the sand and you see a stick going into the water. That stick is like a mole, but instead of a stick it is a big, long path for boats to go on! The path is usually made of stones and dirt so that boats can safely travel to and from the shore. It's like a bridge for ships to park and load passengers and cargo. So it's an important part of a port because it makes it easier and safer for boats to dock and unload goods.