Srimad Bhagvata Mahapurana: Book 10: Chapter 41: Verses 16-25
(My) salutation be to You, 0 Lord of the universe, adored (even) by the gods, the hearing and recital of whose praises brings (supreme) merit, 0 jewel among the Yadus, 0 Narayana of excellent renown ! The glorious Lord said : Accompanied by My elder brother, I shall visit your house (only) when I have slain Kamsa (the enemy of Yadu's race), and bring delight to My (other) relations (as well). Sri Suka continued : Thus spoken to by the Lord, the aforesaid Akrura entered the city like one sad at heart and, having apprised Kamsa of what he had done, returned home. Accompanied by Sankarsana (Balarama) and surrounded by the (other) cowherds, Lord Sri Krsna, who was eager to have a look at the city, fearlessly entered Mathura the next afternoon. (Presently) He saw the city with high gateways (in its fortification wall) and portals (of its houses), made of crystal and fitted with huge doors of gold and embellished with ornamental arches-also of gold-over them. It had granaries etc., of copper and brass, had been rendered difficult of access by a moat and was adorned with gardens and delightful parks. It was (further) graced with sheds of gold erected on the cross roads, mansions and rest-houses also of gold, halls for the meeting together of individuals following a particular trade and other (public) buildings, and was resonant with the noise of pigeons and peacocks perched on small wooden sheds erected in front of houses, platforms under them air-holes and pavements, (all) inlaid with cat's-eyes, diamonds, crystals, sapphires, corals, pearls and emeralds.