This video from the Baha’i World News Service (BWNS) describes how, as construction of the floor for the central plaza of the Shrine of Abdu’l-Baha nears completion, preparations are underway to build the more complex geometric elements of surrounding walls.
You can read the full Baha’i World News Service article here: Shrine of Abdu’l-Baha: First steps taken to raise walls of central plaza
The Universal House of Justice announced plans to begin constructing the Shrine of Abdu’l-Baha in its 2019 Ridvan message (you can read the message here, or listen to it here). The Universal House of Justice stated that the Shrine would be in the vicinity of the Ridvan Garden, between Haifa and Bahji, on land consecrated by the footsteps of Baha’u’llah. If you’re curious why the Shrines of the Bab and Baha’u’llah and many Baha’i holy places are located in Israel, you might wish to check out this Baha’i Blog article: Why Is the Baha’i World Centre in Israel?
You can read more about Abdu’l-Baha, including a biography of His life, His Unique Station, a selection of His Writings, and other articles dedicated to Him here on Bahai.org.