Geography is the study of the Earth and its features and the effect of human activity. It bridges natural and social sciences. There are two main branches: physical geography, which studies natural elements like climate and landforms; and human geography, which examines human populations and activities. Some disciplines of physical geography include geomorphology, glaciology, pedology, hydrology, climatology, biogeography, and oceanography. Eratosthenes was considered the father of geography for writing the first scholarly treatise on the topic and inventing the system of latitude and longitude. Strabo also made major contributions by writing descriptive histories and his work "Geography of Strabo."