Astrophysical evidence suggests that the universe contains a large amount of non-luminous dark matter, but no definite signal has been observed despite concerted efforts by many experimental groups. One exception is the long-debated claim by the DAMA group of an annual modulation in the events observed in their detector using sodium-iodide target material as might be expected from weakly interacting massive particle (WIMP) dark matter interactions. The new COSINE-100 experiment, an underground dark matter detector at the Yangyang Underground Laboratory (Y2L) in Korea is starting to explore this claim using the same medium and now has first results that significantly challenge the interpretations made by DAMA that have stood for nearly two decades. Y2L is operated by the Center for Underground Physics (CUP) of the Institute for Basic Science (IBS) in Korea.