Okay kiddo, let me explain to you what the Iga Ueno Ninja Festa is.
Iga Ueno is a city in Japan where a long time ago, there were special warriors known as ninjas. They were very skilled in using different weapons, like swords or shurikens, and were very sneaky and quick.
Nowadays, people in Iga Ueno celebrate their ninja history every year with a big festival! It's called the Iga Ueno Ninja Festa.
During this festival, people dress up as ninjas and have a parade through the city. There are also lots of cool ninja shows and demonstrations, where you can see real-life ninjas doing their ninja moves and stunts.
There are also lots of fun activities for kids (and adults too!) like throwing shurikens (of course, fake ones) or trying to walk silently like ninjas do.
Overall, the Iga Ueno Ninja Festa is a really fun and exciting way to learn about ninja history and experience a bit of ninja culture. I hope this helps you understand what it's all about!