Promotional value expires Dec 23, 2017. Amount paid never expires. Limit 4 per person, may buy 1 additional as gift. Valid only for option purchased. Valid only for option purchased. Reservation required; subject to weather. 7-day cancellation notice required or fee up to Groupon price may apply. Tours run rain or shine unless there is a threat of severe weather. Tour cancellations due to weather are made the day of the scheduled tour. Does not apply to specialty tours. Valid only for customers between 75 and 265 pounds. Must be redeemed in one visit. Merchant is solely responsible to purchasers for the care and quality of the advertised goods and services. Offer is not eligible for our promo codes or other discounts. Learn about Strike-Through Pricing and Savings