How big is a BMX freestyle park, and what is in it?

• The park: "a facility composed of various ramps and obstacles" designed so riders can compose runs of tricks.
• Size: at least 15 metres wide and 25 metres long. Neither the width nor the length may be more than 60 metres.
• Obstacles: at least three. An obstacle is any feature raised above the level where it sits, and the park's walls can count.
• Safety zone: at least 2 metres on all sides where a rider or bike could be thrown out. Only accredited staff and entered riders may be in it.
• Levels: all on one level, or spread over several raised ones. The base of each level is flat.
• Surface: hard, even and with good grip, "such as wood or concrete", with no gaps, bumps or holes.
• Top events: World Cup events, the world championships and multi-sport Games including the Olympic Games use a park built specifically for BMX, made of wooden ramps.
• Smaller events: existing wood or cement facilities, including public bowls and skateboard parks.
• Flatland area: at least 10 metres by 10 metres and no more than 25 metres either way, with a 1 metre safety zone, a flat solid surface and marked boundaries.
• No changes: riders may not add elements to the field of play or alter it.

The glossary has the park, flatland and the jump.

The size and spacing of the ramps decide which tricks are possible, because height comes from the run-in and the shape of the ramp. Minimum dimensions and a hard surface give riders the speed to get that height. The safety zone is for the moments when a bike leaves the park without its rider.