Palau consists of a couple island chains, which form a part of the larger Melanesian Islands. The country sits in or just off of the Philippines Sea, which is a part of the greater Pacific Ocean. Palau is made up of 25 larger islands and another 300 smaller, uninhabited islands.
The islands of Palau are quite varied as some islands are mountainous, while others are low-lying and made of coralline. Many of the mountainous islands are forested, but even these "mountainous" islands are fairly low-lying as the highest point in the country is just under 800 feet tall (250 meters). Most of the islands are surrounded by coral reefs.
The people arrived from nearly every direction, including Southeast Asia, the Philippines, Polynesia, and Melanesia. Most of the nearby ocean currents run from the east to the west though, which is likely how the Polynesian people arrived. However, these ocean currents aren't enough to attract regular visitors so over time the people on Palau became almost completely isolated and developed a unique culture.