San Cristóbal de La Laguna is a city and municipality in the northern part of the island of Tenerife in the Province of Santa Cruz de Tenerife, on the Canary Islands (Spain). The city is the third-most populous city of the archipelago and the second-most populous city of the island. La Laguna's historical center was declared a World Heritage Site by UNESCO in 1999. In 2003 the municipality started an ambitious Urban Plan to renew this area, that was carried out by the firm AUC S.L. (Arquitectura Urbanismo y Cooperación). The city was the ancient capital of the Canary Islands. La Laguna lies right alongside the city of Santa Cruz de Tenerife, thus the two cities and municipalities form a single large urban center, linked by tram.