When driving down Route 1 (Marine Corp Drive), you will pass the War in the Pacific Memorial Park on the right. Piti (Fisheye) is just after that, again on the right. To avoid the large number of tourists diving, it is best to go in the early AM. Micronesia Diving Assoc. is just across the street and you can get your air or rental gear there. The rental crew is awesome and really helped us. There are often a bunch of needlefish which are mistaken for barracuda. Under the observatory is a sandy bottom, and there is an abundance of activity on the sills of the windows. Overall, this is a great easy-dive. I would recommend watching the tide chart, and going out about an hour before high-tide. That will help with the sometimes LONG walk in!