For an agreed price of $20 million, Bildko, Inc., contracted with Venture to design and build on Venture's commercial plot a 15-story office building. In excavating for the foundation and underground utilities, Bildko encountered a massive layer of granite at a depth of 15 feet. By reasonable safety criteria, the building's foundation required a minimum excavation of 25 feet. When the contract was made, neither Venture nor Bildko was aware of the subsurface granite, for the presence of which neither party had hired a qualified expert to test. Claiming accurately that removal of enough granite to permit the construction as planned would cost him an additional $3 million and a probable net loss on the contract of $2 million, Bildko refused to proceed with the work unless Venture would promise to pay an additional $2.5 million for the completed building. If Venture refuses and sues Bildko for breach of contract, which of the following will the court probably decide? 
Bildko is excused under the modern doctrine of supervening impossibility, which includes severe impracticability.  Bildko is excused, because the contract is voidable on account of the parties' mutual mistake concerning an essential underlying fact.  Venture prevails, because Bildko assumed the risk of encountering subsurface granite that was unknown to Venture.  Venture prevails, unless subsurface granite was previously unknown anywhere in the vicinity of Venture's construction site. 