Seattle, WA

Visitors can explore T‑Mobile Park, a 19.59‑acre baseball venue in Seattle that features natural grass and a retractable roof. The tour includes sections typically closed to the public, such as the press box, luxury suites, the playing field, the dugout, and the visitor clubhouse. Cameras are permitted, though access may vary with scheduled events.
http://seattle.mariners.mlb.com/NASApp/mlb/sea/ballpark/sea_ballpark_history.jsp