WATERVILLE — It’s the heart of the Colby College campus and at one point was the tallest building in Maine. It’s one of the defining features of Waterville seen by passers-by on Interstate 95. And it’s the backdrop of commencement when students prepare to leave the city and enter the world.

Colby College’s iconic Miller Library Tower is part of one of the most important architectural structures on the campus, and its upkeep is no small task.

The tower, which dates to the library’s construction in the 1940s when Colby moved from downtown to Mayflower Hill, underwent several months of maintenance this summer ahead of the start of a new school year. It’s the type of work that’s done on a regular basis every five to 10 years and part of a constant cycle of checking on, maintaining and restoring the tower.

“The library is the center of learning,” said Mina Amundsen, assistant vice president for facilities and campus planning. “It’s the most prominent, pre-eminent building on the campus, so it was consciously designed in a way that announces this is an institution of higher learning. At one point it was the tallest building in Maine – an idea that really illustrates the prominence of education.”

Miller Library is named for Merton Miller, an 1890 Colby graduate who went on to make a fortune in gold in the Philippines.

In 1937, he promised then-Colby President Frank Johnson $50,000 to build a library on the new campus, according to the college.

He sent his first installment in the form of gold shares in 1940. Construction began, but Miller’s payments slowed as World War II progressed, and within a year they stopped altogether after the Japanese flooded Miller’s mines.

Still, the project resumed after the war and the Miller Library was completed in 1947.

At 191 feet, it was the tallest building in Maine when it opened and the college installed a dozen blue neon lights in the top turret to warn local aircraft.

Inside, special wiring protects the tower from lightning strikes and a spiral staircase leads visitors to the balcony level and beyond. The inner workings of the tower clock – the faces of which were replaced in 1997 – can be seen and heard along with the clock’s steady ticking.

The last time the tower was fully renovated was in 2005, when new beams were installed in the structure itself. The weather vane atop the tower, which is original, was also replated in 2005.

It represents the sloop the Hero, which the Rev. Jeremiah Chaplin, Colby’s first president, took from Boston to Augusta with his family before traveling up the Kennebec River to Waterville by longboat to found the college.

The recent restoration work was completed by Mid-Maine Restoration of Edgecomb. It took about three months to paint the entire tower because of the difficulty of access, said Andrew Wilcox, a steeplejack for Mid-Maine Restoration.

The company specializes in painting and restoring church steeples and other tall buildings such as courthouses and libraries around New England.

“This is a pretty iconic building for Waterville,” Wilcox said. “I’ve wanted to paint it since I’ve been doing this. So that was pretty exciting.”