How is the first day of summer determined?

 

In the United States and the rest of the Northern Hemisphere, the first day of summer is the day that the Sun is farthest north. This day is known as the Summer Solstice and occurs on June 20^th or 21^st which also happens to be the longest day of the year.

Source: http://www.calendar-updates.com/info/holidays/us/summer.aspx

What plants can help keep cats out of the garden?

Rue is one of the most common perennial shrubs that help keep cats away because they find the scent offensive. Lemon thyme, lavender, and the scaredy cat plant will also help repel cats from gardens.

Source:  http://www.homeandgardenideas.com/gardening/plants/planting/plants-keep-cats-out-your-garden

What is the longest escalator in the United States?

The longest continuous escalator in the United States and the Western Hemisphere is located in Washington D.C. It is at the Wheaton station of the Washington D.C. Metro system. It is 230 feet long with a vertical rise of 115 feet. It can take approximately 2 minutes 45 seconds to ascend or descend without walking.

Source: http://en.wikipedia.org/wiki/Wheaton_%28Washington_Metro%29

Why is Tax Day April 15?

Since 1955, Tax day has typically fallen on April 15. If April 15 falls on a Friday, Taxes are due the following Monday. If April 15 falls on a Saturday or Sunday, then taxes are due the following Tuesday due to the observance of Emancipation Day in Washington, DC. Which is why this year taxes are due on April 17.

Source: http://en.wikipedia.org/wiki/Tax_Day