Viking River Cruises - Fitness

We are going on the Grand European Cruise itinerary with Viking this Summer and have a question for people who might have taken this itinerary or otherwise cruised with Viking River Cruises in Europe. On Viking's FAQ page, the cruise line states that "In many major cities, you may access nearby First-Class hotels and use their Fitness Center and Spa facilities as part of Viking’s relationship with those hotels. See your onboard Concierge for details." Has anyone taken advantage of this opportunity or heard from others about it? I am curious to know which cities this might be available in.