Trump Hotel sign

The recent placement of the Trump International Hotel & Tower sign on Chicago's riverfront inspired me to take a look at other prominent signs of Chicago skyscrapers. Downtown was once littered with neon and marquee lights, and over the years the identification of building owners has generally become more subdued. However, it certainly hasn't disappeared. Here is a look at the history behind some of the signs topping Chicago architecture downtown.
Congress Hotel

Several of the older signs are on the Historic Michigan Boulevard District, best seen from Lake Shore Drive, heading past Grant Park. Congress Hotel has one of the larger and older signs of the Chicago skyline. When neon signs were developed in the very late 1800s, red was the only color available, and thus its red hue.   
Drake Hotel Oak St

Not many neon signs still exist in Chicago because they are difficult to maintain. The iconic Drake Hotel sign, which was also red, just recently replaced its historic letters with LED lights.
Prudential Plaza

One Prudential Plaza, also facing the space of Millennium and Grant Parks downtown, has a prominent sign. It's hard to believe that it was once Chicago's tallest building. And like many of the other buildings with prominent signs in Chicago, like 77 West Wacker Drive (formerly the United Building) or One North Wacker (formerly UBS Tower), it is specifically in a place where pedestrians, drivers, and people peering out of other buildings can easily see it. Most signage on downtown skyscrapers is on buildings facing the river or the park. Otherwise why bother, right? 
Which leads us to ask - why are most of these old signs on hotels? Hotels don't change names as frequently as office buildings. On non-iconic buildings, it isn't a very big deal. No one really hemmed or hawed about the Morton International Building becoming the Boeing International Headquarters in 2001, for example.
Luckily, some of the original lit signs of Chicago still stand today, and the city always continues to change in the way businesses may communicate through their architecture.