Shuka was a great Brahmana leading a Vanaprastha life in the forest. He was against Asuras and Vajradamshtra, a Rakshasa, sought ways to bring him to their camp. Sage Agastya came to visit Shuka. Vajradamshtra impersonated Agastya and asked for meat to be served. He impersonated Shuka’s wife and served human flesh to Agastya who was able to make out the human flesh. Agastya cursed Shuka to become a flesh-eating Rakshasa. Shuka explained the sequence of events. Agastya relented and said Shuka would be redeemed when he conveys Rama’s message to Ravana and advise Ravana on the principles of Maya.

Picture Credit: D.D Dalvi and Navneet Publications

Malyavan, Ravana’s grandfather, his mother Kaikasi's father advised Ravana. He said that is seeing several bad omens after Sita was brought to Lanka. “Thunders in the sky are untimely and blood is raining from the clouds. Temple deities are shaking and Kali is projecting her canine teeth and laughing. Yama, the God of death is seen everywhere in his dark and strange attire. Please return Sita Devi and ask Rama's forgiveness. Rama is Lord Vishnu, and he will pardon you. Even Yogis overcome samsara by seeking refuge at the feet of Rama.”

Ravana dismissed the advice and asked his grandfather to retire to his palace and rest.

Picture Credit: Dr K.U. Krishnakumar and Guruvayoor Devaswom

Ravana decided to meet with Sita in the garden. Vidyujihva, a magician created a fake head resembling Rama along with a bow like that of Rama's bow. Ravana took this 'severed head' and told Sita that Rama was defeated and was killed. Sarama, Vibhishana's wife, consoled Sita. "Do not be dejected. This is just magic played by the Rakshasa. You are going to hear good news in four days. Your Lord is going to kill Ravana." Sita was calmed listening to Sarama's words of solace.

Picture Credit: D.D Dalvi and Navneet Publications

Angada, the prince of Kishkindha, went to Ravana as commanded by Rama to give him still another chance to harbour peace. "Bring Sita to me and apologize, or else get ready to fight with me. You seem to be sitting behind closed doors but be assured I will destroy everything, and my arrows are ready to kill you.”

Ravana asked his warriors to kill Angada. As they came to attack him, Angada picked them up in his hands and threw them afar. Then he wrecked the palace before jumping up and leaving the scene.

Indrajit fought Angada one on one. Angada killed his charioteer. Hanuman, Jambhavan, Sugriva and Nala fought valiantly. Vanaras were victorious by that evening and the Sun was about to set in the sea. Indrajit hid himself in the sky after getting defeated by Angada. He sent out a Naga Astra on Vanaras and hypnotized everyone as if they were tied by an unseen knot.

Then the gigantic Garuda, the enemy of Nagas, landed there, and immediately the effect of the Naga Astra was gone and the Vanaras were freed. Rama blessed the bird. Vanaras became more enthusiastic in fighting the enemy.

Picture Credit: D.D Dalvi and Navneet Publications

Ravana took Sita in a chariot to show Rama and Lakshmana lying in the battlefield after being hit by Naga Asta. Sita was distraught. Trijada, the female guard, again consoled Sita and told her they would come out of the trance soon. Soon after, Garuda appeared to lifted Rama and Lakshmana out of the effects of Naga Astra.

The war swung in Rama’s favour. Dhumraksha, Akampana, Vajradamshtra and Prahasta (commander in chief) were all slain by Rama’s army.

Picture Credit: Dr K.U. Krishnakumar and Guruvayoor Devaswom

By the time Ravana was killed, Lanka had been devastated. Vibhishana sought a blessing from Rama to build a new capital on the western coast and chose Kelaniya, near Colombo. A Buddhist temple is at the site of Vibhishana's palace and houses the only temple to Vibhishana in the world. There are deities of Vibhishana in temples near Rameswaram but those are not solely dedicated to him. The coronation of Vibishnana by Lakshmana is also represented in a sculpture in Kelaniya.

Source
Footsteps of Rama, Vikrant Pande and Neelesh Kulkarni.
Ramayana in Lanka

Picture Credit
https //kelaniyatemple.lk/

Arthur C Clarke, while diving off the coast of Trinconamalee found artefacts from the original Shiva temple of the Chola period. He also found remnants of an underwater temple. The Shiva Lingam is now consecrated and worshipped in the Koneswarama temple.

Source
Footsteps of Rama, Vikrant Pande and Neelesh Kulkarni.