Idaho's capital is Boise, which is also the largest city in the state. The total population is around 1.5 million people spread across an area of 216,632 square kilometers. The climate in Idaho varies from hot summers with cooler evenings to cold winters without extended periods of bitter temperatures below zero degrees Celsius. The top religions in Idaho are Protestant, Mormon, and Catholic. Important rivers include the Salmon and Snake Rivers, and landmarks include Craters of the Moon National Monument and Hagerman Fossil Beds National Monument.