No continent is crossed by every line of latitude.
You can find Antarctica south of about 60 degrees S, in every line of latitude.
The latitude of the equator is zero. The imaginary line crosses the continents of Africa, Asia, and South America.
The point where they cross is zero latitude / 180° longitude.
There are two "lines" of 10° latitude . . . 10° north latitude and 10° south latitude.In Africa, the 'line' of 10° north latitude crosses Guinea, Ivory Coast, Burkina Faso,Ghana, Togo, Benin, Nigeria, Cameroon, Chad, Central African Republic, Sudan,Ethiopia, and Somalia.The 'line' of 10° south latitude crosses Angola, Democratic Republic of the Congo,Zambia, Malawi, and Tanzania.(You can't get any closer to it than having it cross through.)
Antarctica. The South Pole is at 90 degrees S latitude. The North Pole is at 90 degrees N latitude. All lines of longitude converge at both poles.
Most of the US is located on the North American continent. However, most of the US is not located on the same latitude. If this were true, the US would be one straight horizontal line.
From South Africa, travelling westerly along the 30 degrees line of latitude, the nearest continent is the east coast of South America.
The point at which the equator (0° latitude) and the prime meridian (0° longitude) intersect has no real significane but it is in the Atlantic Ocean.
in the Gulf of Guinea, about 380 miles south of Accra, Ghana.
London is on 51 degrees North so that line of latitude would cross Canada.
"Crossing the Line" is associated with crossing the equator at 0 degrees latitude, not longitude. If you cross the equator (0 degrees latitude) at 0 or 180 degrees longitude, there is an additional status included.