Actually, Tokyo Tower fulfilled two roles, it was an important tourist attraction (over 150 million visitors since the inauguration) and was also the support structure for the antennas broadcasting signals for Japanese media outlets such as NHK or Fuji TV.
But in 2011, when Japan made the transition to digital television, Tokyo Tower was deemed to be too small and the new digital antennas were placed on the new Tokyo Sky Tree. So Tokyo Tower is now just a tourist attraction... but I'm sure it will manage to keep a high number of visitors, especially because of the magnificent views from its two observatories.
Here's a night view, fully lit up by its 176 lights, in its common illumination scheme. The lighting was originally designed by Motoko Ishii, a famous Japanese lighting designer and over time other lighting schemes were added, like the Diamond Veil which was inaugurated in 2008, at the 50 years anniversary.
EXIF info:
Nikon D300
Lens: 18-70mm F/3.5-4.5G
Focal Length: 18mm
Aperture: F/7.1
Shutter Speed: 1/2s
ISO Sensitivity: ISO 200