This area between Veterans Boulevard and Broadway is now occupied by Kaiser Permanente hospital, apartment blocks and some auto repair shops. But it was once home to an early airfield and pilot training center, back in the barnstorming days of aviation.
Early aviator Silas Christofferson started the Redwood City Airport in early 1916. He did not run it for long, as he was killed in a crash on October 31, 1916. After his death, Frank Bryant bought the business and renamed it the Redwood City School of Aviation. Hundreds of would-be flyers trained there, including pioneering aviatrix Helen (Hodge) Harris.
In 1920, Bryant in turn sold the business to WWI veteran pilot Walter Varney. Varney was the founder of an early air mail carrier, which ultimately became part of United Air Lines. Redwood City Airport lasted until the 1930s, when it was subdivided for commercial development, and passed into history. You can find more historical photos of the field, pilots and aircraft at the Peninsula Library System's online photo archive.
The cache is a very easy magnetic mints tin, suitably for a quick grab in this sometimes busy location. Stealth, please!