Even at present, in this last decade of the 2oth Century, marking the end of the second millenium, and the beginning of the third, men still ask the same, most fundamental, of questions: What is the meaning of life? What is happiness? What is truth? Why is it that the superlative, supercolossal strides, advances and successes of science and technology, and all studies designed for the betterment of human living, men and nations of the world over are still acutely suffering from unending justices, population explosion, extreme poverty of famine, continuous fear and exploitation, rampant graft and corruption, wanton vioations of human rights, abominal criminality, pollution and diseases of all kinds - problems of man become global in scope, apalling and apocalyptic in perspective and at present stand acutely pressing for solutions. These are all a herculean task for us humans. With that, i consider the above-mentioned statements to be the greatest mystery of life.
Thanks for asking an interesting question. Have a a great day!