Olympic rings are illuminated during an event to mark six months before the opening of the Tokyo 2020 Olympic Games in Tokyo, Japan, on Jan. 24, 2020. (Photos: Xinhua)

Fireworks explode over the illuminated Olympic rings during an event to mark six months before the opening of the Tokyo 2020 Olympic Games in Tokyo, Japan, on Jan. 24, 2020.

Fireworks explode over the illuminated Olympic rings during an event to mark six months before the opening of the Tokyo 2020 Olympic Games in Tokyo, Japan, on Jan. 24, 2020.

Olympic rings are illuminated during an event to mark six months before the opening of the Tokyo 2020 Olympic Games in Tokyo, Japan, on Jan. 24, 2020.

Fireworks explode over the illuminated Olympic rings during an event to mark six months before the opening of the Tokyo 2020 Olympic Games in Tokyo, Japan, on Jan. 24, 2020.

Olympic rings are illuminated during an event to mark six months before the opening of the Tokyo 2020 Olympic Games in Tokyo, Japan, on Jan. 24, 2020.