Also known as Lanka Kanda, this book describes the Ramayana War between the army of Rama and the army of Ravana. Having received Hanuman's report on Sita, Rama and Lakshmana proceed with their allies towards the shore of the southern sea. There they are joined by Ravana's renegade brother Vibhishana. The apes named Nala and Nila construct a floating bridge (known as Rama Setu) across the sea, using stones that floated on water because they had Rama's name written on them. The princes and their army cross over to Lanka. A lengthy war ensues. During a battle, Ravana's son Indrajit hurls a powerful weapon at Lakshmana, who is badly wounded and is nearly killed. So Hanuman assumes a gigantic form and flies from Lanka to the Himalayas. Upon reaching Mount Sumeru, Hanuman was unable to identify the herb that could cure Lakshmana and so decided to bring the entire mountain back to Lanka. Eventually, the war ends when Rama kills Ravana. Rama then installs Vibhishana on the throne of Lanka. On meeting Sita, Rama asks her to undergo an Agni Pariksha (test of fire) to prove her chastity, as he wants to get rid of the rumors surrounding her purity. When Sita plunges into the sacrificial fire, Agni, lord of fire raises Sita, unharmed, to the throne, attesting to her innocence. The episode of Agni Pariksha varies in the versions of Ramayana by Valmiki and Tulsidas. In Tulsidas's Ramacharitamanas, Sita was under the protection of Agni (see Maya Sita) so it was necessary to bring her out before reuniting with Rama. At the expiration of his term of exile, Rama returns to Ayodhya with Sita and Lakshmana, where the coronation is performed. This is the beginning of Ram Rajya, which implies an ideal state with good morals. Ramayan is not only the story about how truth defeats the evil, it also teaches us to forget all the evil and arrogance that resides inside ourselves. Uttara Kanda concerns the final years of Rama, Sita and Rama's brothers. After being crowned king, Rama passes time pleasantly with Sita. After some time, Sita gets pregnant with twin children. However, despite Agni Pariksha ("fire ordeal") of Sita, rumours about her "purity" are spreading among the populace of Ayodhya. Rama yields to public opinion and reluctantly banishes Sita to the forest, where the sage Valmiki provides shelter in his ashrama ("hermitage"). Here, she gives birth to twin boys, Lava and Kusha, who become pupils of Valmiki and are brought up in ignorance of their identity. Valmiki composes the Ramayana and teaches Lava and Kusha to sing it. Later, Rama holds a ceremony during the Ashwamedha yagna, which sage Valmiki, with Lava and Kusha, attends. Lava and Kusha sing the Ramayana in the presence of Rama and his vast audience. When Lava and Kusha recite about Sita's exile, Rama becomes grief?stricken and Valmiki produces Sita. Sita calls upon the Earth, her mother, to receive her and as the ground opens, she vanishes into it. Rama then learns that Lava and Kusha are his children. Many years later, a messenger from the Gods appears and informs Rama that the mission of his incarnation is over. Rama returns to his celestial abode along with his brothers. It was dramatised as Uttararamacarita by the Sanskrit poet Bhavabhuti. As in many oral epics, multiple versions of the Ramayana survive. In particular, the Ramayana related in north India differs in important respects from that preserved in south India and the rest of southeast Asia. There is an extensive tradition of oral storytelling based on Ramayana in Indonesia, Cambodia, Philippines, Thailand, Malaysia, Laos, Vietnam and Maldives. Father Kamil Bulke, author of Ramakatha, has identified over 300 variants of the Ramayana. There are diverse regional versions of the Ramayana written by various authors in India. Some of them differ significantly from each other.