SAN FRANCISCO (BCN) San Francisco Mayor Ed Lee announced today plans for a major expansion of the city's Moscone Convention Center.

Exhibit space at the center could double with the expansion, the first phase of which is expected to be completed by early 2018, Lee said.
"Conventioneers were telling us they need more exhibit space," he said. "It's still too small for the large conventions."
Lee said plans for the expansion are still being crafted and should be unveiled later this year, and that the city is looking to expand further underground rather than construct a new building.
The expansion is part of a 25-year master plan Lee announced today for the center, which hosts about 50 events annually, according to the mayor's office.