1899–1923 cholera pandemic
The sixth cholera pandemic (1899–1923) was a major outbreak of cholera beginning in India, where it killed more than 800,000 people, and spreading to West Asia, North Africa, Eastern Europe, and Russia. The outbreak of the pandemic is thought to have started at the Haridwar Kumbh Mela.
Source: Wikipedia — 1899–1923 cholera pandemic (CC BY-SA 4.0)