IAAF World Relays 2019 was held in __________.

The International Association of Athletics Federations (IAAF) World Relays 2019 was held in Nissan Stadium, Yokohama, Japan from May 11 to 12, 2019. Total 43 nations participated in the two-day event. The event was organised by the International Association of Athletics Federation (IAAF). It is a biennial event, last time it was held in 2017 in Nassau, Bahamas. The top 10 finishers in the IAAF World Relays 2019 in men's and women's 4x400 m relays event and top 12 finishers in mixed 4x400 m relays event have qualified for the IAAF World Athletics Championship which will be held in Doha, Qatar from September 28 to October 6, 2019.