Rath Dínen was the street that ran between the great halls and graves of the great rulers and heroes of Gondor. Situated on the 5th level in Minas Tirith, its east end was a walled path leading up to the great gate of Fen Hollin.
In Rath Dínen lay the House of The Stewards where Denethor II (Steward of Gondor) found his death, and where Faramir, his son, were saved from the mad will of his father, by Gandalf, Pippin (Peregrin Took) and Beregond guard of the Citadel Gate. Denethor II himself instead lay himself down on the burning bed of his son, breaking the staff of his stewardship on his knee, and with the palantír of the city in his hands, and found peace from the madness the palantír had driven him into.
It was also in this street that Pippin and Merry (Meriadoc Brandybuck) were buried after their death in the years between 64 and 79 in the Fourth Age (or 1485 and 1500 S.R), between the bodies of many great men of Gondor.
Resources:
http://www.annalsofarda.dk/annals-of-arda/Places-index/Places-ME/Rath-Dinen.htm