Unity of nations will be established in twentieth century.

On 29th July 1974, the Universal House of Justice admitted "It is true that Abdu'l-Bahá made statements linking the establishment of the unity of nations to the twentieth century."

Peace Will Come

"It is true that Abdu'l-Bahá made statements linking the establishment of the unity of nations to the twentieth century. For example: '...The fifth candle is the unity of nations--a unity which, in this century, will be securely established, causing all the peoples of the world to regard themselves as citizens of one common fatherland....' And, in 'The Promised Day is Come', following a similar statement quoted from 'Some Answered Questions', Shoghi Effendi makes this comment: 'This is the stage which the world is now approaching, the stage of world unity, which, as Abdu'l-Bahá assures us, will, in this century, be securely established.'

"There is also this statement from a letter written in 1946 to an individual believer on behalf of the beloved Guardian by his secretary:

'...All we know is that the Lesser and the Most Great Peace will come--their exact dates we do not know. The same is true as regards the possibility of a future war; we cannot state dogmatically it will or will not take place--all we know is that mankind must suffer and be punished sufficiently to make it turn to God.'"

(From a letter of the Universal House of Justice, July 29, 1974: Ibid.)

http://bahai-library.com/hornby_lights_guidance_2.html&chapter=4#n1425