Question: Where are the Pera Palace Hotel and Palace of the Porphyrogenitus located?

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Sofitel Winter Palace Hotel: The Sofitel Winter Palace Hotel, also known as the Old Winter Palace Hotel, is a historic British colonial-era 5-star luxury resort hotel located on the banks of the River Nile in Luxor, Egypt, just south of Luxor Temple, with 86 rooms and 6 suites.

Palace Hotel, San Francisco: The Palace Hotel is a landmark historic hotel in San Francisco, California, located at the SW corner of Market and New Montgomery streets.  The hotel is also referred to as the "New" Palace Hotel to distinguish it from the original 1875 Palace Hotel, which had been demolished after being gutted by the fire caused by the 1906 San Francisco earthquake.

Pera Palace Hotel: The Pera Palace Hotel Jumeirah (Turkish: "Pera Palas Oteli" ) is a historic special category hotel and museum hotel located in the Beyoğlu (Pera) district in Istanbul, Turkey.  It was built in 1892 for the purpose of hosting the passengers of the Orient Express and was named after the place where it is located.  It holds the title of "the oldest European hotel of Turkey".

Palace Hotel, Kalgoorlie: "For other hotels named Palace Hotel, see Palace Hotel (disambiguation)."

Caux Palace Hotel: The Caux Palace Hotel is a former palace hotel located in Caux, above Montreux in the Vaud canton, in Switzerland.

Astoria Palace Hotel: The Astoria Palace Hotel is a hotel in Copacabana, Rio de Janeiro, Brazil.  It faces the Copacabana Beach and is located just metres west of the Copacabana Palace Hotel.  It is one of the newest hotels in the area and has 115 rooms.

Palace Hotel, Helsinki: The Palace Hotel is an historic modernist hotel in Helsinki, opened in 1952, the year of the Helsinki Olympic Games.  The building was designed by architects Viljo Revell and Keijo Petäjä, and was constructed during 1949–1952.  In addition to the Palace Hotel and related restaurants, the building hosted also the main offices of the Confederation of Finnish Industry and Employers.  The interiors of the building were furnished by various renowned Finnish interior designers, such as Olli Borg, Antti Nurmesniemi and Olavi Hänninen.

The Taj Mahal Palace Hotel: The Taj Mahal Palace Hotel (Marathi: ताजमहल हॉटेल) is a "Heritage Grand" class five-star hotel in the Colaba region of Mumbai, Maharashtra, India, next to the Gateway of India.  Historically it was known as the "Taj Mahal Hotel" or the "Taj Palace Hotel".  or simply "the Taj".

Palace of the Porphyrogenitus: The Palace of the Porphyrogenitus (Greek: ), known in Turkish as the Tekfur Sarayı ("Palace of the Sovereign"), is a late 13th-century Byzantine palace in the north-western part of the old city of Constantinople (present-day Istanbul, Turkey).  An annex of the greater palace complex of Blachernae, it is the best preserved of the three Byzantine palaces to survive in the city (together with the ruins of the Boukoleon Palace; and the ruins of the Great Palace of Constantinople with its surviving substructures, retrieved mosaics and standing Magnaura section), and one of the few relatively intact examples of late Byzantine secular architecture in the world.

Grand Palace Hotel, Riga: Grand Palace Hotel is a 5 star hotel in Riga, Latvia, in a building originally erected 1877 to house a bank, but now with 56 hotel rooms.  Grand Palace Hotel is member of The Leading Hotels of the World, and has been voted as Latvia's Leading Hotel for six years, latest being in 2010.

Supporting paragraphs: Pera Palace Hotel Palace of the Porphyrogenitus
Answer: Istanbul, Turkey