Valmiki Ramayana Sundara Kanda Sarga 4 Shloka 9
Original Shlokaभवनाद्भवनं गच्छन् ददर्श पवनात्मजः। विविधाकृतिरूपाणि भवनानि ततस्ततः।।5.4.9।।
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भवनात् from one building, भवनम् to another building, गच्छन् going, पवनात्मजः Hanuman, ततस्ततः here and there, विविधाकृतिरूपाणि different kinds of structures, भवनानि buildings, ददर्श saw.
Going from one building to another, Hanuman saw mansions of different kinds structures.