October 28

The first sign of the coming of age of humanity referred to in the Writings of Bahá’u’lláh is the emergence of a science which is described as that “divine philosophy” which will include the discovery of a radical approach to the transmutation of elements. This is an indication of the splendours of the future stupendous expansion of knowledge.

Concerning the “second” sign which Bahá’u’lláh indicates to have been revealed in the Kitáb-i-Aqdas, Shoghi Effendi states that Bahá’u’lláh, “...in His Most Holy Book, has enjoined the selection of a single language and the adoption of a common script for all on earth to use, an injunction which, when carried out, would, as He Himself affirms in that Book, be one of the signs of the ‘coming of age of the human race’”. 
- The Universal House of Justice  (The ‘Notes’ section of the ‘Kitab-i-Aqdas’)