Building the ISS was kind of like the world's most complicated LEGO set, except the pieces were built in different countries, launched into space on rockets, and snapped together while floating 400 kilometers above Earth!

The ISS is the largest human-made object ever to orbit Earth. It weighs about as much as 320 cars and has about as much living space inside as a six-bedroom house. Its solar panels — the big wing-like things that collect energy from the Sun — cover an area bigger than half a football field.

It took 36 Space Shuttle flights and 6 Russian rocket launches just to get all the pieces up there. Astronauts from many different countries helped carry supplies, swap out crew members, and bring up new equipment.

To put the space station together, astronauts had to go outside in spacesuits and work in the vacuum of space. This is called a spacewalk, or an EVA (Extra-Vehicular Activity).
Imagine trying to connect electrical cables while wearing big puffy gloves, floating in zero gravity, with the Earth spinning below you. That's what these astronauts did!

The very first ISS spacewalk happened on December 7, 1998. Two astronauts connected cables between the station's first two pieces. Since then, more than 260 spacewalks have taken place, that's more than in all other space programs put together!
One spacewalk even lasted nearly 9 hours — almost a full school day!

One really cool moment happened in 2007 when astronaut Scott Parazynski, who was also a doctor, used his medical skills to stitch up a torn solar panel while dangling at the very end of two robotic arms stuck together. Like a doctor fixing a wound, but in space!

The ISS isn't just cool to look at — it's a working science laboratory! Scientists use it to run experiments that can only be done in space, where there's almost no gravity (called microgravity).

They study things like:
• How the human body changes in space
• How materials and liquids behave without gravity
• New medicines and technologies that could help people on Earth

The station has been doing science nonstop since the year 2000, and the discoveries keep adding up!

The ISS isn't owned by just one country, it belongs to a team of nations working together. The US, Russia, Europe, Japan, and Canada all play important roles. Each country built different parts, launched them into space, and connected them together.

Every day, astronauts from different countries live and work side by side on the station. Even though these countries sometimes disagree about things back on Earth, they manage to cooperate in space to do something truly incredible. That's pretty amazing!