This is the 8941st most frequent Japanese word.
気球
Hot air balloon.
Here, '気球' refers to the subject of the sentence depicting an object.
気球は空に浮かぶ美しい物体です。
A balloon is a beautiful object that floats in the sky.
In this sentence, '気球' is used as the vehicle for the action of riding.
私たちは気球に乗って景色を楽しみました。
We rode a hot-air balloon and enjoyed the scenery.
Here, '気球' represents the topic of history being described.