Which of the following stadiums was not opened during the late modern era?

Gillette Stadium is the correct answer because it opened in 2002, which places it in the contemporary era of stadium construction rather than the late modern era. The late modern era generally refers to the period from the mid-20th century through the late 1990s, during which many iconic stadiums were built, featuring distinct architectural styles and amenities that reflected that period's trends in sports facility design.

In contrast, Fenway Park, Wrigley Field, and Yankee Stadium were all completed much earlier. Fenway Park opened in 1912, Wrigley Field was established in 1914, and Yankee Stadium first opened its doors in 1923. These stadiums are emblematic of the late modern era, showcasing design elements and construction techniques prevalent during that time. Gillette Stadium, being a product of the early 2000s, incorporates more modern amenities and designs, distinguishing it from the classic layouts of the earlier venues.