When President Trump came to South Korea earlier this month, he spoke to troops at the U.S. Army garrison known as Camp Humphreys — 40 miles south of Seoul — rather than at Yongsan, the main military headquarters in the center of the capital city.

Humphreys has gradually become the hub for American forces on the peninsula, and by next year most most of them will be stationed south of the Han River, which dissects Seoul, under a relocation agreement reached more than a decade ago.

A 3,500-acre base, Humphreys has dramatically expanded over time and is now the largest United States military installation overseas. It houses more than 10,000 soldiers — with a total population of more than 25,000, including families and South Korean troops — and has one of the busiest military airfields in Asia.

See the transformation:

CREDIT: Before/after tool created by NPR Visuals.