What if you could fill a bag with something so light that it floated into the sky? That is exactly what two French men did in 1783. Jacques Charles and Nicolas-Louis Robert built a giant balloon made of silk. They coated the fabric with rubber to keep gas from escaping. Then they filled it with hydrogen, a gas that is much lighter than the air around us. On November 1, 1783, a huge crowd gathered in Paris to watch. The balloon launched from the Tuileries Garden. Charles and Robert rose high above the city. They could see rivers, farms, and forests below. The flight lasted about two hours and covered twenty-seven miles. When they landed in a field, amazed farmers ran toward them. Nobody in that village had ever seen people fly before. This flight proved that hydrogen could lift heavy loads. It was a major step toward modern air travel. Before airplanes were invented more than a hundred years later, balloons were the only way humans could soar above the ground.