HDW

This well-traveled yacht belongs to Paul Allen, co-founder of Microsoft and author of “Idea Man,” a memoir about his life, startups and relationship with former business partner Bill Gates. Espen Øino designed the yacht’s exterior, while Seattle-based Jonathan Quinn Barnett created the initial interior design.

Deputy Prime Minister Sultan bin Abdul Aziz al Saud, Crown Prince of Saudi Arabia, was widely thought to own Al Salamah, which Terence Disdale designed and the German shipyard HDW built in association with Lürssen. The shipyard, which launched the yacht in 1999 under the name Mipos—allegedly for “Mission Possible”—sees the vessel return every so often for maintenance.