WEST MILFORD-Christmas is widely celebrated on Dec. 25, but in Mexico and other lands, another day, Jan. 6, yesterday, is the big observance of the birth of Christ. So it is for Maria-Cristina and Hans Peter Niederstrasser, who were raised in Mexico but have lived here for the last 22 years. A native of Tampico on Mexico's gulf coast, Maria-Cristina received her first Nativity figure, the baby Jesus, as a gift from her Grandmother. She was less than two-years old, but the Christmas gift was to start a lifelong collection of figures. "In Mexico, we call it the Three Wise Kings" observance, she said. There, she said the observance can continue until Feb. 2, the period said to cover the 40 days from when Christ's mother, Mary, gave birth, until she and other women of her era, were allowed to visit the temple. "Then my father started buying something every year, she said. Hans, from Mexico City, recalls: "When we started dating it was a good excuse to give her a present," he said with a smile, recalling that period, 42 years ago. Some of their 120 human figures are more than a half-century old. Then they have "at least another 100 animals," Maria-Cristina notes. Everything from "tiny chickens to cows and donkeys." Each holiday season the couple devotes a sizeable portion of their living room to the Nativity display and its focus changes each year. They start to set up the house on "the first Sunday of Advent," by putting out their other collection: Complete Nativity scenes of varying sizes, down to one created inside a pistachio shell. "Any horizontal surface becomes the place for a Nativity," said Hans. "We start doing the large display on Dec. 15," notes Hans, and it takes thredays to set up the primary display in their living room. While most of the exquisitely detailed figures are modestly priced figures from four towns in Mexico that specialize in their production, their collection features figures or Nativity scenes from many parts of the world. A retired pharmaceutical company employee, Hans and his wife lived for a time in Rio de Janeiro, Brazil, and have several from that South American nation. However, Maria-Cristina, an adjunct professor of Spanish and Portuguese at William Paterson University, says other countries represented in their collection include Germany, Italy, France, two from Russia, Argentina, El Salvador, Peru, Bolivia, the United States, Kenya, Angolla and Nigeria. "A friend just brought back a piece from Alaska," noted Hans. The couple's most expensive figure is from the Aix-En-Provence region of France, another area than specializes in Nativity figures. With such an extensive collection, will Maria-Cristina keep collecting? "Yes, if I find something I like."