Is the eiffl tower and big ben monuments?

Yes, both the Eiffel Tower and Big Ben are considered monuments.

The Eiffel Tower is a wrought iron lattice tower on the Champ de Mars in Paris, France. It is named after the engineer Gustave Eiffel, whose company designed and built the tower for the 1889 World's Fair. The Eiffel Tower is 324 metres (1,063 feet) tall, and is one of the most recognizable landmarks in the world. It is the most-visited paid monument in the world; 6.91 million people ascended it in 2015.

Big Ben is the nickname for the Great Bell of Westminster, and the clock tower housing it within the Palace of Westminster in London, England. Officially known as the Elizabeth Tower since 2012, in commemoration of Queen Elizabeth II's Diamond Jubilee, it was previously known as the Clock Tower. In 1859 it became the largest four-faced chiming clock in the world—a title it held for over a century, until 1908. The term Big Ben is often, mistakenly, used to refer to both the clock and the tower.