What is the most popular series on TLC Channel?

According to Nielsen ratings and viewership data, the most popular series on TLC Channel is "90 Day Fiancé." The reality television series follows couples who apply for the K-1 visa, which allows foreign fiancés of American citizens to enter the United States. "90 Day Fiancé" and its various spin-offs have gained substantial popularity, with high ratings and a large fan base. It is known for its dramatic storylines and the exploration of cultural and personal differences between the couples.