What is the fine-grained topic of the following text: Jobless and with a ticking travel visa time-bomb attached to them in the United States, one Singaporean couple did this: Walked more than 2.5km along the majestic Golden Gate Bridge of San Francisco, spend almost 11 hours moving up and down the ageless Grand Canyon on a mule, and drove through the dry marshes of the iconic Trona Pinnacles. Only return the topic.
Singaporean couple's travel experiences in the United States during unemployment