Where do we begin? What do we want to see? Do we have time to see it all? Just the enormous size of the Field Museum of Natural History in Chicago is an exhausting proposition. Located at 1400 South Lake Shore Drive, in the Museum Campus, at the south end of Grant Park, overlooking Monroe Harbor and Lake Michigan, it is recognized as one of the three premier museums in the United States, along with the American Museum of Natural History in New York City and the Museum of Natural History at the Smithsonian Institution in Washington D.C. The massive building, which was opened in 1921, covers 480,000 square feet of exhibit space on three levels and displays 40 million specimens and objects, a full range of existing biodiversity, gems, meteorites, fossils, anthropological collections and cultural artifacts. Its library contains 275,000 books, journals and photo archives on biology, geology, archaeology and ethnology. Are you tired yet? Two million people visit the museum annually. They are mostly attracted to the museum's five permanent exhibitions. Personally, as a historian, I am always fascinated by the Inside Ancient Egypt exhibit, which includes 23 human mummies, an ancient marketplace, a three-story replica of the tomb of the son of the last pharoah of the Fifth Dynasty and 5,000-year-old hieroglyphs. Adults and children alike have been drawn to Sue, the Tyrannosaurus rex, since the exhibit was unveiled in 2000. It is the largest T. rex specimen ever discovered. It is 67 million years old and measures 40.5 feet long by 13 feet tall and once weighed 8.4 to 14 tons. Other must-see exhibits are the animal exhibits and dioramas such as Nature Walk, Mammals of Asia and Mammals of Africa; Evolving Planet, which follows the evolution of life on Earth over four billion years; and Ancient Americas, which covers 13,000 years of human ingenuity and achievement in the Western Hemisphere. Founded in 1893, the museum originated from the 1893 World's Columbian Exposition. It was added to the National Register of Historic Places in 1975. The more you see, the more you want to see. Allow four or five hours to appreciate it all.