The first 100 days are a presidential milestone and a benchmark that dates back almost a century. The 100-day marker began with Franklin D. Roosevelt in 1933 when he hit the ground running during the Great Depression and called for a special session.

Trump makes a momentous political comeback, breaking through the "blue wall" to win 312 electoral votes. Trump becomes only the second US president in history to be elected to non-consecutive terms, following Grover Cleveland (the 22nd and 24th US president).

On the campaign trail, the economy was seen as one of Trump's strengths. But recently, it's been a driving force in lower approval ratings.