1 Low blood levels of calcium may be caused by low levels of protein (albumin) in the blood, because about half of all calcium in the blood is attached to albumin. 2  For this reason, an ionized calcium level (which is not attached to albumin) and a blood albumin level may also be measured. Low blood levels of calcium may be caused by low levels of protein (albumin) in the blood, because about half of all calcium in the blood is attached to albumin. 2  For this reason, an ionized calcium level (which is not attached to albumin) and a blood albumin level may also be measured.
Manitou Cliff Dwellings. The Manitou Cliff Dwellings are a group of relocated Anasazi ruined cliff dwellings and a museum located just west of Colorado Springs, Colorado on U.S. Highway 24 in Manitou Springs. The Anasazi Museum was established in 1904 and opened to the public in 1907.
Credit: Foursquare 2 Tulum You cannot find a Mayan ruin with a more dramatic location. This small but breathtaking city is set on a cliff top by the Caribbean Sea, just two hours south of Cancun. You canât climb on these structures, but Tulum does have one of the worldâs most unique beaches at the foot of the cliff.