National Gallery limiting visitors to London of Da Vinci exhibit to prevent "Gallery Rage"

 The National Gallery in London will be a cap on the number of visitors admitted to an exhibition Leonardo da Vinci to come to reduce the so-called "rage gallery" caused by overcrowding.

180 tickets per half hour will be sold for the show, which opens in November. However, the health and safety rules dictate that 230 tickets per hour can be sold.

While the Gallery could lose more than 10,000 pounds ($16,336) by this measure, it will prevent a rush of visitors Sainsbury wing of the Museum.

"We have looked hard at the problems caused by popular exhibitions in recent years and decided to take measures in advance what is likely to be one of the most important shows of our history," said Director Nicholas Pennyas reported by The Telegraph.

The exhibition, which begins advance booking Tuesday, will feature the half of the 14 da Vinci surviving paintings on wood. Among the works will be: the Madonna of the rocks, the Madonna Litta and the Lady with an ermine (also known as the Portrait of Cecilia Gallerani), La Belle Ferronière.

National Public Gardens day: 10 under the Radar gardens to visit this holiday of the mothers

May 6 marks the 3rd National Public Gardens day annual. Created to raise awareness of the importance of the public gardens in the promotion of stewardship of the environment and the conservation of plants and water, the day will be see some 500 events across the country to celebrate the public gardens of America.

Most of the events, for families, schools and tourists, will last through the end of week (hint: a visit would be a great treat for last minute mother's day).

National Public Gardens day always takes place the Friday before mother's day and aims to commemorate the beginning of the spring.

Out in your hometown or travel to a public garden close to celebrate spring - not to mention the good mother ol '.

All the gardens mentioned below are free to enter. Check the Web site of national public gardens day for gardens coupons which charge admission Friday.

National Public Gardens day: 10 under the Radar gardens to visit this holiday of the mothers

May 6 marks the 3rd National Public Gardens day annual. Created to raise awareness of the importance of the public gardens in the promotion of stewardship of the environment and the conservation of plants and water, the day will be see some 500 events across the country to celebrate the public gardens of America.

Most of the events, for families, schools and tourists, will last through the end of week (hint: a visit would be a great treat for last minute mother's day).

National Public Gardens day always takes place the Friday before mother's day and aims to commemorate the beginning of the spring.

Out in your hometown or travel to a public garden close to celebrate spring - not to mention the good mother ol '.

All the gardens mentioned below are free to enter. Check the Web site of national public gardens day for gardens coupons which charge admission Friday.

Text and photos courtesy of the American public gardens Association.

Considered by many as a leader in the conservation of plants, Denver Botanic Gardens is working with the programs of the State of data on the rare plants of Colorado, monitor endangered plant species and collect and store the seeds. The gardens of Denver provides stewardship of the environment for more than 60 species of rare and endangered plants throughout the State.

Sleeping controller on duty at the Reagan National

A controller of air traffic at Ronald Reagan Washington National Airport falls asleep duty early Wednesday morning, leaving the silent control tower and forcing the pilots of two aircraft trade on their own territory, the National Transportation Safety Board said today.

The controller, who had 20 years of experience, including 17 to the Reagan National, was suspended Thursday earlier by the Federal Aviation Administration as continues his investigation.

The report of the NTSB, which does not refer to the controller, said he had worked its fourth quarter consecutive night, from 10 a.m. to 6 a.m., and that "the fatigue human issues are one of the regions studied."

"I am determined to go to the bottom of this situation for the public safety," FAA administrator Randy Babbitt said in a statement announcing the suspension of the controller.

"As a former pilot, I am personally shocked that this controller failed its responsibility to help these two aircraft, land" he said. "Fortunately, at no time was either flat radar contact and our backup system launched to ensure the safe of two aircraft landing.

Pilots of the plane, American Airlines and United Airlines each said that they had been in contact with regional air traffic controllers turned off the coast of the Reagan National Tower for approach and landing.

But as the aircraft by radio their claims to land in the capital, early Wednesday morning, they heard silence.

"American 1900, so that you are aware that the tower was is apparently not inhabited," a regional controller said the plane pilots, according to radio recordings obtained by ABC News. "If you expect to go into an uncontrolled airport."

The pilot has carried out an overview of the airport - aviation routine procedure - before landing on its own without help from the ground.

Fifteen minutes later, United flight 628 of Chicago was also unable to communicate with the Tower of Reagan.

"The aircraft went as an uncontrolled airport," a regional Comptroller said on the recording. "It is already well happened.".

The pilot also assimilated United airport without driver and landed safely.

Federal transportation officials now lead a controller air comprehensive review of staffing in airports across the country.

While Reagan National is composed of multiple controllers of air traffic during the day, moving to the day the day is managed by a single controller because there are no departures from the overnight and a few arrivals.

But travel from midnight to other major US airports, including New York John Fitzgerald Kennedy and LaGuardia, Chicago O'Hare and Boston Logan, all two service controllers.

Richmond, Virginia, and Andrews Air Force Base are two regional airports which have only a tower for the midnight shift controller.

"The reality is that we should probably never have that a controller at a major airport anytime, anywhere," said expert John Nance aviation. "But the fact that it is Washington, D.C., obviously speeds up issues like that."

Secretary of transportation Ray LaHood has taken a measure unusual late Wednesday to immediately order a second controller of the air traffic at Reagan National Airport on the midnight shift.

"It is not acceptable to have a single controller in the Tower of air traffic management in the airspace this criticism," LaHood said in a statement. "I also asked FAA administrator Randy Babbitt to examine staffing levels in other airports across the country."

A traffic controller air veteran contacted by ABC News, said the incident would have presented not a danger to passengers, because pilots are trained to Earth without air traffic control. But he added that it was very unusual.

"It is a big problem when two aircraft at the Washington National Airport are not able to communicate with the tower", said Dick Marakovitz, a controller for 27 years. "It's a big problem."

American Airlines flight 1012, a Boeing 737, had 91 passengers and six crew on board. United Airlines flight 628, an Airbus A320, had 63 passengers and five crew members.

Reagan National Airport serves some 18 million passengers per year.

ABC News Devin Dwyer has contributed to this report.