stumble upon (?.)

• alight upon
• arrive at
• arrive upon
• blunder upon
• bump into
• chance upon
• come across
• come at
• come on
• come up against
• come upon
• discover serendipitously
• encounter
• fall in with
• fall upon
• get at
• happen upon
• hit upon
• light upon
• meet up with
• meet with
• pitch upon
• reach
• run across
• run into
• run up against
• strike upon
• stumble on
• tumble on