While grocery sales were once largely the domain of small chains like Mars, today it faces competition from mass discounters like Walmart and Target, drug stores, club chains and dollar stores as well as online retailers like Amazon. Longtime competitors like Giant grew much larger and growing retailers such as Wegmans and Harris Teeter entered the Baltimore market. Other new rivals, such as Whole Foods Market and Trader Joe's, attracted a following in the fast-growing natural and organic food niche.