Also stylistically spelled as salacot.
The boy in the picture is wearing the traditional Filipino wide-brimmed hat salakot, which is usually made of rattan or reeds.
There are a few variations on the salakot, usually involving materials or a slight difference in the slope towards the brim or towards the top center.
Angeles City is famous for this structure in the shape of a salakot.
Having grown up seeing it, the locals are flummoxed that the Salakot Arch is considered a tourist attraction. They probably think every other city has its own salakot-shaped arch.