In addition, there are descendants of immigrants who came from other Caribbean islands, including St. Kitts and Nevis, Antigua, St. Vincent, Montserrat, Tortola, St. Croix, St. Thomas, and Guadeloupe. They worked on sugarcane plantations and docks and settled mainly in the cities of San Pedro de Macorís and Puerto Plata. Puerto Rican, and to a lesser extent, Cuban immigrants fled to the Dominican Republic from the mid-1800s until about 1940 due to a poor economy and social unrest in their respective home countries. Many Puerto Rican immigrants settled in Higüey, among other cities, and quickly assimilated due to similar culture. Before and during World War II, 800 Jewish refugees moved to the Dominican Republic.