San Diego

In 1850, following the Mexican-American War and the signing of the Treaty of Guadalupe Hidalgo, California was admitted to the Union as the 31st state. San Diego, which had been a part of the Mexican territory of Alta California, officially became part of the United States. This marked the beginning of its development as a city under American control.

The Panama-California Exposition was held in San Diego from 1915 to 1917 to celebrate the opening of the Panama Canal, and to promote San Diego as the first U.S. port of call for ships traveling north after passing through the canal. The exposition was held in Balboa Park and had a profound impact on the development of the city's architectural landscape, showcasing Spanish Colonial Revival style.

Comic-Con International: San Diego, commonly known as San Diego Comic-Con (SDCC), was first held in 1970. It has grown into the largest convention of its kind in the world, celebrating primarily comic books and science fiction and fantasy films, television, and related popular art forms. The convention brings together a diverse lineup of panels, screenings, and exhibitors attracting fans and professionals from across the globe.

The San Diego Trolley, a light rail system that has since become an essential part of the city's public transportation network, officially began operation on July 4, 1981. It was the first modern light rail system in the United States, marking the beginning of efforts to reintroduce mass transit to Southern California cities after decades of reliance on cars and buses.

The San Diego Convention Center opened in 1989 and has since served as the venue for numerous major events, including Comic-Con International, trade shows, and conferences. The center's location on the waterfront, combined with its modern architectural design and large floor space, has made it a cornerstone for tourism and commerce in San Diego.

The San Diego Natural History Museum, established in Balboa Park since 1933, underwent a significant expansion in 1997. The new Arthur and Elizabeth Schlesinger Hall of Plants opened, doubling the museum's space and allowing for expanded exhibits and educational programs focused on the natural world of Southern California and Baja California.

Petco Park, the home of the San Diego Padres Major League Baseball team, was completed in downtown San Diego. The stadium, which has a seating capacity of over 40,000, is known for its unique architecture and urban setting, integrating historic buildings with a modern design. It replaced Qualcomm Stadium as the home of the Padres and has become a key venue in the city for sports and events.

The San Diego River Conservancy Act was established to preserve, restore, and enhance the San Diego River area. The conservancy focuses on both environmental protection and public access, aiming to maintain the river as a usable natural and cultural resource. This initiative reflects broader environmental efforts within California to balance urban development with sustainability and habitat preservation.

The new San Diego Central Library opened in 2013 after over a decade of planning and development. The nine-story library features a distinctive dome, a state-of-the-art auditorium, and numerous community areas, serving as a modern cultural and educational hub for the city. The library is rated Gold for Leadership in Energy and Environmental Design (LEED), showcasing a commitment to sustainability.

Horton Plaza Park, a historic urban park located in downtown San Diego, underwent a major renovation and officially reopened in 2016. The revitalized space includes interactive fountains, performance areas, and an amphitheater, and is designed to serve as a dynamic community space that connects the historical elements of downtown with new urban development initiatives.