SAN FRANCISCO Putting a major cultural institution into mothballs is not an easy thing to do. Repurposing it for the 21st century is an even bigger challenge. After 10 years of fundraising, five years of construction and $488 million in expenditures, the verdict is in: San Francisco's new Academy of Sciences, which opened Saturday in Golden Gate Park, was well worth the wait. Simply put, it's a landmark as captivating for its architectural statement as for the wondrous exhibits inside. The old Academy, a beloved if slowly crumbling complex that had occupied the site since 1916, was damaged beyond repair in the 1989 Loma Prieta earthquake and demolished in 2004.