35 East Wacker, also known as the Jewelers' Building, is a 40-story 523 ft (159 m) historic building in the Loop community area of Chicago, Illinois, United States, located at the intersection of Wabash Avenue and East Wacker Drive, facing the Chicago River. It was built from 1925 to 1927, and was co-designed by Joachim Giæver and Frederick P. Dinkelberg. At the time of its completion in 1927, it was the tallest building in the world outside New York City. Formerly the Pure Oil Building and North American Life Insurance Building, 35 East Wacker was listed in 1978 as a contributing property to the Michigan–Wacker Historic District on the National Register of Historic Places, and was designated a Chicago Landmark on February 9, 1994.

The Loop, one of Chicago's 77 designated community areas, is the central business district of the city and is the main section of Downtown Chicago. Home to Chicago's commercial core, it is the second largest commercial business district in North America after Midtown Manhattan in New York City, and contains the headquarters and regional offices of several global and national businesses, retail establishments, restaurants, hotels, and theaters, as well as many of Chicago's most famous attractions. It is home to Chicago's City Hall, the seat of Cook County, and numerous offices of other levels of government and consulates of foreign nations. The intersection of State Street and Madison Street is the origin point for the address system on Chicago's street grid. Most of Grant Park's 319 acres are in the eastern section of the community area. The Loop community area is bounded on the north and west by the Chicago River, on the east by Lake Michigan, and on the south by Roosevelt Road.