The "Landmark Tower" is one of the main features of this area, and visitors can pay 800 Yen to take an elevator (That has a "power level" gauge and reaches a maximum speed of 750m/min!) up to the observation deck on the 69th floor. The observatory deck provides an amazing view of the area, and also sports a souvenir section, and a restaurant-bar that serves drinks, food and ice cream, and purchasing any items would grant you an exclusive sofa seat that has an excellent view over Minato Mirai! Upon exiting the observatory and taking the elevator back down, visitors would find themselves in a large shopping mall that even has a Pokemon Center!
Visitors can also take a stroll around the scenic park, or go the theme park for a exhilarating ride (As can be seen from the large ferris wheel and the several roller coasters in the image above), visit the cup noodle museum that allows you to customize your own cup noodles, or the various shopping and dining options available in the several shopping malls.
The Nippon Maru is a tall ship that was built in 1930. It used to serve as a training ship for the Japanese Merchant Marines. It is now open to the public as part of the Yokohama Port Museum.
All in all, Minato Mirai is an extremely beautiful area and is also very accessible, and you can reach there via the "Minato Mirai" train station along the Minatomirai Line. There are many attractions packed into a small area and it is extremely easy to explore on foot.