The beautiful notes 6yo Elena hid for her parents to find after she died of cancer.

In 2006, the Desserich family were in the process of renovating their Cincinnati, Ohio, home when their five-year-old daughter, Elena, fell ill.

The little girl, who “loved art and dresses” and “always ate her vegetables first” began to slightly slur her words and started to have trouble walking.

After taking her to the emergency room, doctors originally told her parents, Keith and Brooke, that nothing was wrong. But after Elena’s paediatrician ordered an MRI, the family was given the worst possible news.

"A doctor entered her [hospital] room crying," dad Keith told The Mirror.

"Not fully understanding, we offered our condolences, only to have her tell us she was crying because of the news she was about to deliver."

Elena was diagnosed with Diffuse Intrinsic Pontine Glioma (DIPG), a rare childhood brain tumour for which there is no cure.

She was given less than five months to live.

Nine months later, little Elena passed away in her bed. It was only then her family discovered the incredible gift she had left behind.

Over a nearly two-year period, Keith and Brooke found hundreds of notes the little girl had written for her family and her younger sister, Grace, to find after her death.

Elena had hidden the notes - which included drawings and messages like "I love you Mom, Dad and Grace" and "I'm worry I'm sick" - in drawers, between the pages of books, in the china cabinet and inside bags.

"After she lost her battle, slowly we started to put our lives and our house together. We found the first few notes and thought we'd forgotten about them," Keith, now 41, said.

"Only after discovering many notes, and receiving a call from my mother, telling us she'd found a note in Elena's dresser at her house, did we finally understand what Elena intended.

"We would find notes for nearly two years as we slowly opened boxes, drawers and Christmas ornaments."

The couple believes Elena - who they describe as "wise beyond her years" - was leaving them messages of love and hope to give them strength after she had passed away, and that she got the idea after seeing her father write notes of his own.

"We believe Elena was doing for us what we were doing for Grace," said Keith.

"At times, she would see me writing and I would explain that I was writing notes to Grace to tell her about the two of them.

"We believe that Elena was simply doing this for us."

Elena's sister grace was just three-years-old when Elena was diagnosed with cancer, and would never know her older sister.

Nearly 10 years on, and Brooke and Keith still carry Elena's notes with them every day, a constant reminder of their little girl.

"Brooke has her note, I have mine. They are tucked away in our briefcases - always with us, never out of reach," he said.

In 2009, the family published a book about Elena's notes and story, Notes Left Behind, which became a New York Time's Bestseller.

All proceeds from the book went towards The Cure Starts Now, the charity started by the Desserichs the year after Elena's death and is dedicated to finding a cure for all forms of cancer, "one child at a time".

Despite the world hearing about Elena's story, there are some notes that the family has chosen to keep private.

"To this day, we have only shared half of the notes we wrote for her sister, preferring to keep the others for her only," Keith said.

LISTEN: Andrew Daddo and Holly Wainwright discuss how we should introduce our kids to grief.