WASHINGTON — She was sitting in a wheelchair as they carried her son's casket into the Capitol Rotunda on Friday.

Roberta McCain, 106, held granddaughter Meghan McCain's hand and lifted a handkerchief to dab her eyes. Wearing lipstick, pink blush and a polka dot white blouse, she sat silently as congressional leaders and Vice President Mike Pence lauded Sen. John McCain, who died last weekend at age 81.

When the tributes were over, Roberta was the last member of the family to touch his flag-draped casket. She crossed herself afterward.

Many obituaries have been quick to mention the McCain family's prestigious lineage within the American military. The senator's father and grandfather — both of whom shared his name — were the first father and son in Navy history to become full admirals.

But often overlooked is the influence McCain's mother had on his upbringing and political life. Now, Roberta has outlived the child she still calls "Johnny."

Roberta, who lives in Washington, spent years crisscrossing the globe, often alongside her identical twin sister, Rowena. She has ridden through the Jordanian desert in the dark of night, hopped a ferry to Macau and trekked through Europe on less than $5 per day.

Roberta and Rowena were born in 1912 when William Howard Taft was president. They grew up traveling the country with their father, a successful oil wildcatter who retired young to raise his children. The family would travel for weeks, sometimes along the California coast or by the banks of the Great Lakes.

Those trips would later serve as the blueprints for what Sen. McCain described as his mother's "mobile classroom" — one that could show her children the world's wonders in ways a four-walled classroom could not.

"My mother grew to be an extroverted and irrepressible woman," Sen. McCain wrote in his memoir, Faith of My Fathers.

Roberta met her future husband, John S. McCain Jr., as a 19-year-old student at the University of Southern California. McCain Jr., known as "Jack," was a young Navy ensign serving on the battleship USS Oklahoma, whose home port at the time was in Long Beach, Calif. Another ensign, who'd taken Roberta out a few times before, brought her onto the Oklahoma for a visit when she crossed paths with Jack.

Roberta and Jack fell in love, but Roberta's mother was so unhappy that her daughter could end up with a sailor that she banished Jack from her family home, Sen. McCain wrote. That did not deter Roberta. Instead, she and Jack eloped one weekend in Tijuana, Mexico, in 1933. The following Monday, she went back to USC to finish her exams.

For all her doting on her children and husband, Roberta took the reins of her own life, too. In 2007, she described to the New York Times how she and her sister would drive through the world's open roads.

Once, when traveling through France in her 90s, Roberta was told she was too old to rent a car. So instead, she bought one. At the end of her vacation, she had the car shipped back to the East Coast, where she picked it up and drove it to San Francisco, she told the New York Times.

In his memoir, McCain wrote that he "became my mother's son," often by "emulating and exaggerating" her characteristics. For example, she was exuberant, so he was rowdy.

"She taught me to find so much pleasure in life that misfortune could not rob me of the joy of living," he wrote.