Not until 1998 did al Qaeda undertake a major terrorist operation of its own, in large part because Bin Laden lost his base in Sudan. Ever since the Islamist regime came to power in Khartoum, the United States and other Western governments had pressed it to stop providing a haven for terrorist organizations. Other governments in the region, such as those of Egypt, Syria, Jordan, and even Libya, which were targets of some of these groups, added their own pressure. At the same time, the Sudanese regime began to change. Though Turabi had been its inspirational leader, General Omar al Bashir, president since 1989, had never been entirely under his thumb. Thus as outside pressures mounted, Bashir's supporters began to displace those of Turabi. The attempted assassination in Ethiopia of Egyptian President Hosni Mubarak in June 1995 appears to have been a tipping point. The would-be killers, who came from the Egyptian Islamic Group, had been sheltered in Sudan and helped by Bin Laden. When the Sudanese refused to hand over three individuals identified as involved in the assassination plot, the UN Security Council passed a resolution criticizing their inaction and eventually sanctioned Khartoum in April 1996. A clear signal to Bin Laden that his days in Sudan were numbered came when the government advised him that it intended to yield to Libya's demands to stop giving sanctuary to its enemies. Bin Laden had to tell the Libyans who had been part of his Islamic army that he could no longer protect them and that they had to leave the country. Outraged, several Libyan members of al Qaeda and the Islamic Army Shura renounced all connections with him. Bin Laden also began to have serious money problems. International pressure on Sudan, together with strains in the world economy, hurt Sudan's currency. Some of Bin Laden's companies ran short of funds. As Sudanese authorities became less obliging, normal costs of doing business increased. Saudi pressures on the Bin Laden family also probably took some toll. In any case, Bin Laden found it necessary both to cut back his spending and to control his outlays more closely.

What was the assassination of President Hosni Mubarak a tipping point for?

In 1990, the U.S. Custom House in New York City was renamed after Hamilton. In 1880, his son John Church Hamilton commissioned Carl Conrads to sculpt a granite statue, now located in Central Park, New York City. One statue honoring Alexander Hamilton in Chicago was mired in controversy, at least concerning the surrounding architecture. Kate Sturges Buckingham (1858-1937), of the Buckingham Fountain family, commissioned the monument. Its impetus was that Treasury Secretary Hamilton "secured the nation's financial future and made it possible for her own family to make its fortune in grain elevators and banking. Consequently, John Angel was hired to model a figurative sculpture and the Finnish architect Eliel Saarinen was to create a "colossal architectural setting" for it. The proposed 80-foot tall columned shelter was poorly received. By Ms. Buckingham's death in 1937, the sculpture's setting. location and design were uncertain. Conspiracy allegations surfaced, and the matter became mired in litigation. After the courts ordered the construction to be completed by 1953, the trustees hired architect Samuel A. Marx. The structure was completed, had structural problems, and was eventually demolished in 1993. The statue was gilded, and is still on display. A statue, by James Earle Fraser, was dedicated on May 17, 1923, on the south terrace of the Treasury Building, in Washington.

From 1937 to 1953 what legal proceeding tied up the construction of the statue?

Earth processes have not changed over time. The way things happen now is the same way things happened in the past. Mountains grow and mountains slowly wear away. The same process is at work the same as it was billions of years ago. As the environment changes, living creatures adapt. They change over time. Some organisms may not be able to adapt. They become extinct. Becoming extinct means they die out completely. Some geologists study the history of the Earth. They want to learn about Earths past. They use clues from rocks and fossils. They use these clues to make sense of events. The goal is to place things in the order they happened. They also want to know how long it took for those events to happen.
What do geologists study to give them clues about the Earth's past?