Known as the world's most vertical city, Hong Kong ran out of burial space in the 1980s. With over seven million inhabitants living on just 426 square miles, the city is one of the world's most densely packed—and so are its cemeteries. Seemingly endless rows of nearly identical headstones creep up hillsides on the periphery of the city, with many tombs only arms-length distance apart. Space is so limited that graveyards are multi-denominational, with Buddhists, Muslims, Christians, Jews, Hindus, and Parsee buried side by side. The Guardian has a surprisingly beautiful photo essay on Hong Kong's maze-like cemeteries, with impressive aerial shots of the neatly stacked rows.