Surprising as it may be to most non-scientists and even to some scientists, Albert Einstein concluded in his later years that the past, present, and future all exist simultaneously. In 1952, in his book Relativity, in discussing Minkowski's Space World interpretation of his theory of relativity, Einstein writes:

Since there exists in this four dimensional structure [space-time] no longer any sections which represent "now" objectively, the concepts of happening and becoming are indeed not completely suspended, but yet complicated. It appears therefore more natural to think of physical reality as a four dimensional existence, instead of, as hitherto, the evolution of a three dimensional existence.

Einstein's belief in an undivided solid reality was clear to him, so much so that he completely rejected the separation we experience as the moment of now. He believed there is no true division between past and future, there is rather a single existence. His most descriptive testimony to this faith came when his lifelong friend Besso died. Einstein wrote a letter to Besso's family, saying that although Besso had preceded him in death it was of no consequence, "...for us physicists believe the separation between past, present, and future is only an illusion, although a convincing one." (SOURCE)
The video below discuss multiple theories on time, and perhaps the most important notion to take away is that we all live in our own time. What may seem like a long time to you could seem like just a split second to someone else. The notion that time is an illusion stems from the idea that we all perceive time in different ways. What do you think? Is time an illusion? Let us know in the comment section below.