The final round's challenge would be the same, but with a single obstacle three levels high.

So at once the greatest single obstacle to the happiness of mankind had been removed.

It's the biggest single obstacle to the creation of churches.

For many people, lack of time is the single biggest obstacle to fitness.

For younger pitchers, the single greatest obstacle might be focus.

It remains the single biggest obstacle to Iraq's political and physical reconstruction.

The permanent married family is the greatest single obstacle to this".

"That is the single biggest obstacle to a major investment in mass transit," he said.

Corruption is the single biggest obstacle to the delivery of aid to the poor.

Either of them alone would be bad enough; together, they're the greatest single obstacle we face in the Lords.