The most interesting place to visit in the Black Sea region is the city of Istanbul, which for several centuries was the capital of the Ottoman Empire. There are several resorts along the coast. There will be no large hotels like in the Mediterranean Sea region, but there you will find the same sandy beaches and beautiful nature.
You should visit Istanbul to get acquainted with the culture and history of the Byzantine and Ottoman empires. Most attractions are in the historical Sultanahmet district: the Hagia Sophia, Blue Mosque, Topkapi Palace, Süleymaniye Mosque, and the Basilica Cistern. It will be very interesting to have a boat trip along the Bosphorus, as well as visit the Dolmabahçe Palace.
Most of the beach resorts are located closer to Sinop. Samsun resort does not look like a European city. Rize and Trabzon resorts are located near Georgian border. In Amasra resort you can see the sights of the Roman and Genoese periods.