The fortnight from across the globe (January 15-January 31)

Glow-in-the-dark blue waves caused by the phenomenon known as harmful algal bloom or "red tide" are seen at night near Sam Mun Tsai beach in Hong Kong on January 22, 2015. Algal blooms occur when there is a sharp growth in algae population in a water system, and are considered harmful when resulting in negative impacts on other organisms. Picture taken using long exposure