This is a medieval styled falling grid (I don't know if that's correct, I translated it, if it's wrong, please let me know!) which used to block enemies from your kingdom. I tried to add some redstone to the fences so that you could flick a lever and it would go up and down, but I didn't find any tutorials, neither am I that good with redstone.
The build contains a bridge, where you could add lava, water or cacti below. There is a big room, that can be decorated to your preferences, for example with armor stands and chests for swords, bows and arrows to quickly defend your kingdom. The gate also has two towers leading into the castle wall. I tried to make it look a bit more comfortable to walk on from the back, to create a safe feeling for your citizens.
This gate was also used in my project "Large Kingdom Base".



Credits go to Mojang.