More than 125 million Americans were under the highest level of extreme heat alerts during a wave of above-average temperatures.

The deadly heat wave across the eastern half of the country has made for some scary situations. Tens of millions in major cities across the northeast faced record high temperatures on Tuesday, the worst day of an oppressive heat wave that has spread since late last week.

Several cities in the eastern United States have faced record high temperatures due to a climate phenomenon known as the "heat dome."