Most expensive things in the world
Payroll
There's about 3.3 billion working people in the world. Minimum wage varies widely by country, from about 8 cents/hour in India, to about $1.10/hour in China, to $15/hour in Australia. Working hours also range widely, so this is a very rough guesstimate. US, China, and India alone add to $2.066 billion/hour. If we use their blended rate for the remainder of the working population, we get to $4.65 billion/hour. Maybe about 10 trillion per year for everybody.
Water
All living things require water. Fortunately, the opposite is not true. That is, things don't require the absence of water to stay dead. The Earth has about 333 million cubic miles of water. At an average cost of $1.50 per 100 gallons, assuming that price includes the cost to desalinate the water, that's just under 5.5 quintrillion dollars. In other words. about 5,500,000 trillion dollars.
Christians
The total wealth of all Christians is over 100 trillion dollars. This is equivalent to 20 trillion Taco Bell Nacho Crunch Double-Stacked Tacos, 40 trillion Burger King Mini Shakes, 10 trillion McDonald's Iced Teas, and 30 trillion 7-11 Big Bite Hot Dogs.
Real Estate
The total value of all real estate in the world is now over 300 trillion dollars. That makes it more valuable than Christianity and everybody's annual wages put together!
Energy
The total annual energy supply is somewhere around 14,000 million tonnes of oil equivalent. This is about 162,820 TWh's, which is 162,820,000,000,000 kWh's. At an average price per kWh of 12 cents, this is about 19.5 trillion dollars annually.