Hijiyama-kōen is a hilly tree-filled park just outside Hiroshima city centre. It's noted for its cherry blossoms in spring, and autumn foliage, and is a top spot for a stroll. It's also home to the Hiroshima City Museum of Contemporary Art, and the Hiroshima City Manga Library.
Take the number 5 tram (for Hiroshima port), or walk about 20 minutes south of JR Hiroshima Station. The Hiroshima sightseeing loop bus also stops here.