A billionaire philanthropist was mysteriously found dead last week on board a luxury cruise ship. 

Nicole Wertheim, 82, was pronounced dead on April 20 in her room onboard the residence ship, The World, as she was sailing the Pacific Ocean en route to Polynesia, The Miami Herald reports. 

Crew members onboard the ship told her daughter, Erica Wertheim Zohar, that her cause of death was listed as heart-related. The Daily Mail has reached out to The World for comment.

Wertheim's death came as she was being honored by charity-focused online magazine SocialMiami as the Philanthropist of the Year in recognition of a $10 million gift she and her ex-husband, Herbert Wertheim, made in 2013 to Florida International University to create the Nicole Wertheim College of Nursing and Health Sciences.

The then-couple had also announced in 2019 they were donating $10 million to the school to create FIU's School of Music and Performing Arts - the largest gift to a school of music at a public university.

Erica accepted the honor on her mother's behalf amid her year-long cruise.

Then, after the ceremony in Miami ended, Erica said she tried to call her mother, but the phone kept ringing.

It was only later that Erica and her sister Vanessa said they learned that 'she was already pursuing a final horizon,' they wrote in a family memorial. 

'She left this life at the exact moment the city she helped build had paused to say "thank you,"' Erica added, calling it 'a poignant irony.' 

Nicole, born Nicole Laurenti, was born in France and came to the US in the 1960s to work as a model and married Herbert Wertheim in 1969.

The two originally lived together on a 22-by-52 foot houseboat moored on the Miami River that had leopard-print walls, a red sink, black counter tops and no other appliances, according to the Miami Herald.

A broom from Sears served double duty to hang their clothes, and their closest neighbor was the occasional manatee that drifted by.

It was 'very 60s,' Nicole told the outlet in 2005.

Dr. Herbie, as he came to be known, would leave the houseboat to work at his optometry office, where Nicole served as the bookkeeper and assistant.

When the optometry business then started to do well, the Wertheims put down a $2,000 down payment toward a $16,000 purchase of two and a half acres of land in South Florida, where they built their first home.

Then in 1971, Herbie founded Brain Power Inc to make optical lens tints and ophthalmic instruments and chemicals, including the development of the UV400 tint, which deflects UV rays in glasses. 

Nicole helped her husband set up displays at trade shows when the company was first starting out, and the couple eventually amassed a fortune of more than $3 billion through investments and proceeds from the business, according to Forbes. 

But after Nicole became a mother, she and her then-husband started focusing on endowments and scholarships.

They created the Dr Herbert and Nicole Wertheim Family Foundation in 1977 and in 2015, joined the Giving Pledge alongside other billionaires like Bill Gates and Warren Buffett, promising to donate much of their wealth.

She had planned to donate much of her fortune to philanthropy, to support women and also victims of narcissistic abuse, a cause Nicole believed needs wider awareness, Forbes reports.

Much of the donations the couple made during their life together went to Florida International University, where her name now adorns many of the buildings on campus.

Following her passing, university president Jeanette M Nuñez described Nicole in a statement as a 'remarkable champion and benefactor of FIU whose compassion, generosity and vision have left an indelible mark on our university and our community.'

Nuñez went on to note that the university nominated Nicole in 2023 for induction as an honorary member of Sigma Theta Tau International, the Honor Society of Nursing for her donations to the field.

The university president called it a 'rare tribute reserved for those whose dedication in the field transcends the ordinary.'

'What set Nicole apart was not the scale of her generosity, but the sincerity of her presence,' Nuñez said. 'She was never transactional. She showed up.'

Dr Juan Cendan, dean of FIU's Herbert Wertheim College of Medicine, also wrote in a message to her daughters: 'While Nicole Wertheim often remained outside the spotlight, the depth of her commitment, insight and resolve was clear to those within the FIU community who had the opportunity to work with her.

'For more than five decades, she was a true partner in the vision and generosity that made so many transformative gifts possible,' Cendan wrote.

'Her perspective, values and steady guidance played an essential role in the philanthropic spirit that has touched countless lives through FIU.'

A good portion of the more than $280 million in educational gifts the couple made during their marriage was spent outside FIU as well - including $50 million for the School of Optometry at University of California Berkeley, $100 million to the University of Florida for UF Scripps Institute of Biomedical Innovation and Technology and $25 million to University of California San Diego for the School of Public Health.

However, Nicole's daughters said it was their mother's decision to divorce their father over his infidelity after 54 years of marriage in July 2023 that most inspired them.

She had also sued Herbie and their charitable foundation last year, alleging he forged her signature and misappropriated funds in the couple's foundation, but the suit was dismissed as part of the divorce settlement's division of assets. 

'My mother was my best friend and my hero,' Erica told the Miami Herald. 'She taught all of us to stand up for what you believe, no matter your age.

'She had a quiet strength,' Erica continued. 'She was the true essence of beauty, brains and grace, but most of all, a gentle and selfless love.'

Dr. Vanessa Wertheim, a nurse and educator, added that their mother 'was the definition of resilient, graceful and kind.

'She was unconditional in her love, forthcoming with her wisdom and unwavering in her philanthropy.'

In the memorial for their mother, the sisters also described Nicole's decision to seek a divorce from Herbie as 'the ultimate act of protection - protecting her own dignity and the integrity of the family legacy she had spent a lifetime building.

'...She wanted her legacy to protect other women from the invisible patterns of control she had navigated herself, ensuring that the strength she found at 80 could be shared with those who felt they had no voice.

'She proved that the greatest gift one can give isn't a building - it's the example of a life lived with dignity, fierce love and the strength to stand tall until the very end.'

Nicole is survived by her daughters and four grandchildren.