Lord Ramachandra is an important incarnation of Krishna, the supreme lord, and His pastimes are briefly summarized by Srila Prabhupada in his purport to a verse from the ancient scripture Srimad-Bhagavatam. This is actually Srila Prabhupada's unedited writing from the original commentary on the Bhagavatam that he wrote before coming to the west in 1966. Please enjoy!
Nara devatwam apannah sura karya chikirsaya
Samudra nigrahadini chakre viryani atahparah
Nara -- human being, devatwam -- divinity, apannah -- having assumed the form of, sura -- the demigods, karya -- activities, chikirsaya -- for the purpose of performing, samudra -- the Indian ocean, nigrahadini -- controlling, chakre -- did perform, viryani -- superhuman, prowess, ataparah -- there after.
In the eighteenth incarnation of the Lord, He appeared as King Rama and in order to perform some pleasing work for the demigods, He did exhibited superhuman prowess in the acts of controlling the Indian ocean and then killing the atheist king Ravana on the other side of sea.
The Personality of Godhead Sri Rama assumed the form of a human being and appeared on the earth for the purpose of doing some pleasing work for the demigods or the administrative personalities for maintaining the orders of the universe. Sometimes great demons and atheist like Ravana and Hiranyakashipu and many others become very famous on account of advancing material civilization by the help of material science and other activities with a spirit of challenging the established order of the Lord. For example the attempt of flying over to other planets by material means, is a challenge over the established order. The conditions of each and every planet are different and different classes of human beings are accomodated there for particular purposes mentioned in the codes of the Lord. But puffed up by tiny success in material advancement sometimes the godless materialist challenges the existence of God. Ravana was one of them and he wanted to deport ordinary men to the planets of Indra (heaven) by material means without any consideration of the necessary qualifications. He wanted that a staircase may be built up directly reaching the heavenly planet so that people may not be required to undergo the routine of pious work for qualifying oneself to enter into that planet. He wanted to do many other similar work against the established rule of the Lord. Even he challenged the authority of Sri Rama the Personality of Godhead and kidnapped His wife Sita. Of course Lord Rama came to chastise these atheist class of men by the prayer and desire of the demigods and He therefore took up the challenge of Ravana and the complete activity is the subject matter of Ramayana. Because Lord Ramachandra was the Personality of Godhead He exhibited some superhuman activities which no human being including the materially advanced Ravana could do them. Lord Ramachandra prepared a royal road on the Indian ocean with stones which were floating on the water. The modern scientist have searched out the region of weightlessness but it is not possible for such scientist to bring in weightlessness anywhere and everywhere. But because weightlessness is the creation of the Lord by which He can make the gigantic planets fly and float in the air, so He made the stones even within this earth into weightlessness and prepared a stone bridge on the sea without any supporting pillars, That is the display of all powerfulness of God.