I built the original Marco Simone [1989] but they had to do quite a bit to my design to host the Ryder Cup. It was really a challenge and wonderful experience. It is laid out around a castle that was built in the year 1000, and there’s a tower that dates back even earlier and was the original lookout for Rome. It’s about 10 miles from Rome, and you can see the dome of St. Peter’s Basilica.

What is the biggest difference between designing a course in the United States and the rest of the world?

In Europe, they didn’t do land development with golf courses. They built a golf course and then they built houses on the outside of it, not up and down the corridors of the fairways. The golf course is the core and then homes are built around it. In the United States, they build 300 homes and a golf course and you try to get as many homes as you can along the fairways.

What is the biggest challenge in designing a golf course?

Environmentalists. You can’t take down trees. You can’t cross rivers. You can’t fill them in. It’s hard to get permission to pipe them. It’s a lot different today than it was 25 years ago. It’s worldwide. In fact, the rules are stricter in Europe and the rest of the world than they are in the United States. In Japan, the problem is terrain. Anything that is flat, they save for rice. In Tokyo proper, the land is real expensive. The farther you get away from the city, the cheaper the land becomes.

What do you consider your masterpiece?

The Trump International Golf Club in West Palm Beach, Fla. We had to move three million tons of dirt. We built hills and mounds and played with elevation. There’s a 50-foot drop off the 18th tee. We put in creeks. We put in waterfalls.

You have designed a couple of courses for Donald Trump. How is he as a boss?

The Trump International was the first one he had ever done, and he didn’t know anything about golf course design. He knew about buildings and real estate, but he’d come on the weekends when he was at Mar-a-Lago. He wanted dramatics, and sometimes that wasn’t the best thing for the course.

It was the most fun I ever had doing a golf course. It was a $40 million project. He was the best boss I have ever had.