Arima onsen is one of the oldest and most famous hot springs in Japan. It is well known that Toyotomi Hideyoshi, who was a warrior in 16th century, also cherished the Arima Onsen.
There are two types of onsen available; one is called kinsen or gold spring which is a red brown color, and the other one is called ginsen, or silver spring which is clear with no color. It takes only 30minutes from Sannomiya Station and an hour from Osaka area by train to Arima Onsen.
Mt. Maya is the highest mountain in Kobe. The night view from Kikuseidai observatory is known as one of the three best night scene viewing spots in Japan.
There is a path where florescent stones are used in an attempt to mirror the Milky Way. You can take a cable car or ropeway to go up. You could also hike up the mountain.