Related Clues:

• It could fall on a foot
• Vault feature
• Viaduct feature
• ''Duke'' starter
• Impressive entrance
• Sole partner
• Real creep
• Tongue-in-cheek
• Design feature of many a viaduct
• Foot back
• Darned spot, often
• Achilles’ soft spot
• Bend over backward
• ___ of Constantine (landmark in 45-Across)
• It's big in St. Louis