1. On September 18, 1830, the first passenger train in the United States ran from Albany to Schenectady, in what is now New York State. The train, called the Mohawk & Hudson Railroad, consisted of a single locomotive and passenger car, and marked the beginning of the railroad age in the United States.

2. On September 18, 1882, the first electric streetcars went into service on the Bowery in New York City. The streetcars replaced horse-drawn carriages and were powered by electricity from overhead wires. The new electric streetcars were faster, more reliable, and more comfortable than the old horse-drawn carriages.

3. On September 18, 1927, the Columbia Broadcasting System (CBS) was formed in New York City. CBS quickly became one of the most successful radio and television networks in the United States, broadcasting news, sports, music, and entertainment programming to millions of listeners and viewers.

4. On September 18, 1961, United Nations Secretary-General Dag Hammarskjöld was killed in a plane crash while flying to negotiate a ceasefire in the Congo. Hammarskjöld, a Nobel Peace Prize laureate, was widely regarded as one of the most effective and influential leaders in the history of the United Nations.

5. On September 18, 2001, the World Trade Center in New York City was reopened for the first time since the September 11 terrorist attacks. The complex had been closed for several days while rescue and recovery efforts took place, and the reopening was seen as a symbol of resilience and solidarity in the wake of the tragedy.