In 1997, a child’s helium balloon was responsible for causing a standstill on the MTR in Hong Kong that lasted 12 hours and held up 100,000 commuters. On the MTR, you are not permitted to bring balloons at any time.The unfortunate event took place on October 2nd, when a young girl of five years old accidentally let go of her balloon while riding on a train. The balloon soared up into the air and became stuck in the doors of the train, which prevented the doors from closing. The girl’s balloon triggered a 12-hour standstill on the MTR, which held up 100,000 commuters. The train was forced to stop at the next station, and the MTR was forced to stop as well.Because of this occurrence, the MTR has decided to prohibit the use of balloons on all of its trains and in all of its stations. Even though the ban has been in effect for nearly 20 years, balloons can still be spotted on the MTR from time to time, which causes delays and inconveniences.