As of my last knowledge update in September 2021, some of the most expensive hotels in the world are renowned for their luxury, exclusivity, and exceptional services. Keep in mind that hotel prices can vary based on seasons, special events, and other factors. Here are some of the most expensive hotels known at that time:

1. The Royal Penthouse Suite, Hotel President Wilson, Geneva: This suite in the Hotel President Wilson is often listed as one of the most expensive hotel rooms in the world, with rates reportedly exceeding $80,000 per night. It offers stunning views of Lake Geneva and the Swiss Alps and comes with luxurious amenities and security features.
2. The Mark Penthouse, The Mark Hotel, New York City: Located on Manhattan’s Upper East Side, The Mark Penthouse is one of New York City’s most expensive hotel suites, with rates exceeding $75,000 per night. It features a 5-bedroom suite with a private rooftop terrace.
3. The Empathy Suite, Palms Casino Resort, Las Vegas: Designed by artist Damien Hirst, the Empathy Suite is one of the most expensive hotel suites in Las Vegas, with rates reported at around $100,000 per night. It is a 2-story suite with a private cantilevered pool overlooking the city.
4. The Four Seasons Hotel Ty Warner, New York City: The Ty Warner Penthouse Suite at the Four Seasons in New York City is a luxurious accommodation option, with rates reportedly around $50,000 per night. It offers breathtaking views of the city and Central Park.
5. The Hilltop Villa, Laucala Island Resort, Fiji: Laucala Island Resort offers an exclusive hilltop villa with rates reported at around $50,000 per night. The private villa comes with a pool, dedicated staff, and stunning views of the Pacific Ocean.
6. The Royal Villa, Grand Resort Lagonissi, Athens: The Royal Villa at the Grand Resort Lagonissi in Athens, Greece, is a lavish accommodation option, with rates reportedly exceeding $50,000 per night. It offers a private pool, direct beach access, and personalized services.
7. The Penthouse Suite, Hotel Martinez, Cannes: The Penthouse Suite at the Hotel Martinez in Cannes, France, offers luxury and elegance, with rates reported at around $45,000 per night. It comes with a rooftop terrace and panoramic views of the Mediterranean Sea.
8. The Hilltop Estate, La Réserve Ramatuelle, French Riviera: This private villa at La Réserve Ramatuelle offers exclusive luxury, with rates reportedly around $40,000 per night. It features a private pool, gardens, and stunning sea views.
9. The Ritz-Carlton Suite, Ritz-Carlton Moscow, Russia: The Ritz-Carlton Suite at the Ritz-Carlton Moscow offers opulence and luxury, with rates reported at around $20,000 per night. It provides panoramic views of the Kremlin and Red Square.
10. The Penthouse Suite, Hotel Cala di Volpe, Sardinia: This luxurious penthouse suite in Sardinia offers stunning sea views and exclusive amenities, with rates reportedly around $20,000 per night.

Please note that hotel prices can change over time, and new luxury accommodations may have been introduced since my last update. Additionally, prices can vary depending on seasonal demand, availability, and any special packages or offers.