Many of the puzzle clues relate to body systems, organs, functions and health.

Monitors allow you to study an area before entering it and to play back past events that offer puzzle clues.

Many of the puzzle clues explore places and laws related to immigration.

Many of the puzzle clues relate to food's role in helping us stay healthy.

Many of the puzzle clues have to do with discoveries, animals, space, health, and the climate.

Many of the puzzle clues relate to locations around the world.

Many of the puzzle clues relate to civil right leaders, black artists, writers and singers.

Many of the puzzle clues relate to chilling stories and their authors.

Many of the puzzle clues examine technological innovations that changed the world during the 20th century.

Many of the puzzle clues test your knowledge of the presidents.