The show premiered on Wednesday, May 20, 2015, at 8:00 pm EDT,[1] and ran for seven straight weeknights, with a weekend break.

Good Morning America weekend co-anchor and Nightline anchor Dan Harris hosted the show's second season.

Successfully doing so results in the challenger taking the contestant's spot, and starting their own journey towards 500 questions.

Answering all 500 questions will bring the total prize up to €2,500,000, which has yet to receive in the first series of five 90-minute episodes.

Whenever the contestant had two consecutive misses, the backup chose the next category in an attempt to force them out of the game.

This format included three special question types, which were randomly hidden on the category board.

"Triple Threat" questions had three or more correct answers, and the contestant had 10 seconds to give three of them.

"Battle" questions also had multiple answers, and the contestant and backup took turns giving one each; as soon as either participant missed, their opponent won.

If a contestant accrued their third consecutive miss during a Lightning Round, the backup had to play the rest of it.