The umbrella term in Rule 16.1 for four course features that always carry free relief: animal holes, ground under repair, immovable obstructions, and temporary water. Ground under repair covers maintenance holes, piled material awaiting removal, and protected wildlife habitat; temporary water covers puddles from rain or irrigation, not a course's built-in water hazards; immovable obstructions cover paths and fixtures. Regardless of which of the four is actually in the way, the fix is identical: find the nearest point of complete relief, not nearer the hole and in the same area of the course, then drop within one club-length of it. Grouping them under one rule is why the procedure never changes even when the obstacle does.