LOUISVILLE, Ky. (WDRB) -- Thousands of students from around the world are in Louisville this week. They are showing off robots they've built with their own hands.

The competition started with an impressive parade of nations inside Freedom Hall.

"And now, our host nation...The United States of America," said the announcer.

There are 1,000 teams from around the world and the biggest applause was for the teams representing the USA.

It's all part of the annual Vex Worlds 4-day robotics competition.

"We built it, we programmed it, we've competed it several times before now," said Keeley Slade, a John Hardin High School Student. "And we qualified for worlds and here we are."

They've spent hundreds of hours creating something with no instructions or manuals, but with just their brains and a challenge to build a robot that can throw or shoot a ball.

Matthew Vuleta is also a student at John Hardin. He said, "First thing that came to mind was kind of like throwing it."

"And we ended up going with the catapult design," said Slade.

To make sure there's a level playing field, the teams and robots have the same task or challenge.

Jason Morrella is President of the REC Foundation. He said, "At the higher level, it is called nothing but net. They are picking up objects, which are different size balls and they're having to shoot them into nets or goals and they have some other obstacles they have to navigate through but at the end of the day they're trying to score more points than the other teams are scoring."

The competitors are just teenagers. Organizers say you can only imagine what the contestants will be doing by the time they're in their 20s.

"I can't wait," said Vuleta.

But for now, they're just looking forward to winning this week and seeing next year's challenge.

"We will probably all be up that night sketching out ideas and thinking of different ways to complete the challenge," said Slade.

The champions will be crowned on Saturday.

Copyright 2016 by WDRB News. All rights reserved.